INQUIRIES INTO HUMAN FACULTY AND ITS DEVELOPMENT
First issue of this Edition 1907
PREFACE TO THE SECOND EDITION
After some years had passed subsequent to the publication of this book in 1883, its publishers, Messrs. Macmillan, informed me that the demand for it just, but only just warranted a revised issue. I shrank from the great trouble of bringing it up to date because it, or rather many of my memoirs out of which it was built up, had become starting-points for elaborate investigations both in England and in America, to which it would be difficult and very laborious to do justice in a brief compass. So the question of a Second Edition was then entirely dropped. Since that time the book has by no means ceased to live, for it continues to be quoted from and sought for, but is obtainable only with difficulty, and at much more than its original cost, at sales of second-hand books. Moreover, it became the starting point of that recent movement in favour of National Eugenics (see note p. 24 in first edition) which is recognised by the University of London, and has its home in University College.
Having received a proposal to republish the book in its present convenient and inexpensive form, I gladly accepted it, having first sought and received an obliging assurance from Messrs. Macmillan that they would waive all their claims to the contrary in my favour.
The following small changes are made in this edition. The illustrations are for the most part reduced in size to suit the smaller form of the volume, the lettering of the composites is rearranged, and the coloured illustration is reproduced as closely as circumstances permit. Two chapters are omitted, on “Theocratic Intervention” and on the “Objective Efficacy of Prayer.” The earlier part of the latter was too much abbreviated from the original memoir in the _Fortnightly Review_, 1872, and gives, as I now perceive, a somewhat inexact impression of its object, which was to investigate certain views then thought orthodox, but which are growing obsolete. I could not reinsert these omissions now with advantage, unless considerable additions were made to the references, thus giving more appearance of personal controversy to the memoirs than is desirable. After all, the omission of these two chapters, in which I find nothing to recant, improves, as I am told, the general balance of the book. FRANCIS GALTON.
LIST OF WORKS.
The Teletype: a printing Electric Telegraph, 1850; The Narrative of an Explorer in Tropical South Africa, 1853, in “Minerva Library of Famous Books,” 1889; Notes on Modern Geography (Cambridge Essays, 1855, etc.); Arts of Campaigning: an Inaugural Lecture delivered at Aldershot, 1855; The Art of Travel, or Shifts and Contrivances available in Wild Countries, 1855, 1856, 1860 (1859);
fourth edition, recast and enlarged, 1867, 1872; Vacation Tourists and Notes on Travel, 1861, 1862, 1864; Meteorographica, or Methods of Mapping the Weather, 1863; Hereditary Genius: an Enquiry into its Laws and Consequences, 1869; English Men of Science: their Nature and Nurture, 1874; Address to the Anthropological Departments of the British Association (Plymouth, 1877);
Generic Images: with Autotype Illustrations (from the Proceedings of the Royal Institution), 1879; Inquiries into Human Faculty and its Development, 1883; Record of Family Faculties, 1884; Natural Inheritance, 1889; Finger-Prints, 1892;
Decipherments of Blurred Finger-Prints (supplementary chapters to former work), 1893; Finger-Print Directories, 1895;
Introduction to Life of W. Cotton Oswell, 1900; Index to Achievements of Near Kinsfolk
of some of the Fellows of the Royal Society, 1904; Eugenics: its Definition, Scope, and Aims (Sociological Society Papers, vols. I. and II.), 1905; Noteworthy Families (Modern Science);
And many papers in the Proceedings of the Royal Society, Journals of the Geographical Society and the Anthropological Institute, the Reports of the British Association, the Philosophical Magazine, and Nature.
Galton also edited:
Hints to Travellers, 1878;
Life-History Album (British Medical Association), 1884, second edition, 1902;
Biometrika (edited in consultation with F.G. and W.F.R. Weldon), 1901, etc.;
and under his direction was designed a Descriptive List of Anthropometric Apparatus, etc., 1887.
LIST OF MEMOIRS.
The following Memoirs by the author have been freely made use of in the following pages:–
1863: The First Steps towards the Domestication of Animals (_Journal of Ethnological Society_);
1871: Gregariousness in Cattle and in Men (_Macmillan’s Magazine_);
1872: Statistical Inquiries into the Efficacy of Prayer (_Fortnightly Review_);
1873: Relative Supplies from Town and Country Families to the Population of Future Generations (_Journal of Statistical Society_);
Hereditary Improvement (_Fraser’s Magazine_); Africa for the Chinese (_Times_, June 6); 1875: Statistics by Intercomparison (_Philosophical Magazine_); Twins, as a Criterion of the Relative Power of Nature and Nurture (_Fraser’s Magazine_, and
_Journal of Anthropological Institute_); 1876: Whistles for Determining the Upper Limits of Audible Sound (_S. Kensington Conferences_, in connection with the Loan Exhibition of Scientific Instruments, p. 61); 1877: Presidential Address to the Anthropological Department of the British Association at Plymouth (_Report of British Association_);
1878: Composite Portraits (_Nature_, May 23, and _Journal of Anthropological Institute_); 1879: Psychometric Experiments (_Nineteenth Century_, and _Brain_, part vi.);
Generic Images (_Nineteenth Century; Proceedings of Royal Institution_, with plates);
Geometric Mean in Vital and Social Statistics (_Proceedings of Royal Society_);
1880: Visualised Numerals (_Nature_, Jan. 15 and March 25, and _Journal of Anthropological Institute_); Mental Imagery (_Fortnightly Review; Mind_); 1881: Visions of Sane Persons (_Fortnightly Review_, and _Proceedings of Royal Institution_);
Composite Portraiture (_Journal of Photographical Society of Great Britain_, June 24);
1882: Physiognomy of Phthisis (_Guy’s Hospital Reports_, vol. xxv.); Photographic Chronicles from Childhood to Age (_Fortnightly Review_); The Anthropometric Laboratory (_Fortnightly Review_); 1883: Some Apparatus for Testing the Delicacy of the Muscular and other Senses (_Journal of Anthropological Institute_, 1883, etc.).
_Memoirs in Eugenics_.
1901: Huxley Lecture, Anthropological Institute (_Nature,_ Nov. 1901); Smithsonian Report for 1901 (_Washington_, p. 523); 1904: Eugenics, its Definition, Scope and Aims (Sociological Paper, vol. i., _Sociological Institute_); 1905: Restrictions in Marriage, Studies in National Eugenics, Eugenics as a Factor in Religion (Sociological Papers, vol. ii.); 1907: Herbert Spencer Lecture, University of Oxford, on Probability the Foundation of Eugenics.
The following books by the author have been referred or alluded to in the following pages:–
1853: Narrative of an Explorer in Tropical South-Western Africa (_Murray)_;
1854: Art of Travel (several subsequent editions, the last in 1872, _Murray_);
1869: Hereditary Genius, its Laws and Consequences (_Macmillan_);
1874: English Men of Science, their Nature and their Nurture (_Macmillan_).
PREFACE TO THE SECOND EDITION
Origin and object of book.
VARIETY OF HUMAN NATURE
Many varieties may each be good of its kind; advantage of variety; some peculiarities are, however, harmful.
Large number of elements in the human expression; of touches in a portrait; difficulty of measuring the separate features; or of selecting typical individuals; the typical English face; its change at different historical periods; colour of hair of modern English; caricatures.
(See Appendix for three Memoirs describing successive stages of the method).–Object and principle of the process; description of the plate–composites of medals; of family portraits; of the two sexes and of various ages; of Royal Engineers; the latter gives a clue to one direction in which the English race might be improved; of criminals; of the consumptive; ethnological application of the process.
Anthropometric Committee; statistical anomalies in stature as dependent on age; town and rural population; athletic feats now and formerly; increase of stature of middle classes; large number of weakly persons; some appearances of weakness may be fallacious; a barrel and a wheel; definition of word “eugenic.”
It is the attribute of high races; useful stimuli to activity; fleas, etc.; the preservation of the weakly as exercises for pity; that of foxes for sport.
Sensation and pain; range and grades of sensation; idiots; men and women; the blind; reading by touch; sailors; paucity of words to express gradation.
SEQUENCE OF TEST WEIGHTS
(See also Appendix, p. 248).–Geometric series of weights; method of using them; the same principle is applicable to other senses; the tests only measure the state of faculties at time of trial; cautions in constructing the test weights; multiplicity of the usual perceptions.
WHISTLES FOR AUDIBILITY OF SHRILL NOTES
(See also Appendix, p. 252).–Construction of them; loss of power of hearing high notes as age advances; trials upon animals; sensitivity of cats to high notes; of small dogs and ponies.
Want of anthropometric laboratories; of family records; opportunities in schools; Admiralty records of life of each seaman; family registers (see also 220); autotypes; medical value of ancestral life-histories (see also 220); of their importance to human eugenics.
UNCONSCIOUSNESS OF PECULIARITIES
Colour blindness usually unsuspected; unconsciousness of high intellectual gifts; of peculiarities of mental imagery; heredity of colour blindness in Quakers; Young and Dalton.
Objects of statistical science; constancy and continuity of statistical results; groups and sub-groups; augival or ogival curves; wide application of the ogival; method; example; first method of comparing two ogival groups; centesimal grades; example; second method of comparing ogival groups; statistical records easily made with a pricker.
Caprice and coyness of females; its cause; observations of character at schools; varieties of likings and antipathies; horror of snakes is by no means universal; the horror of blood among cattle is variable.
CRIMINALS AND THE INSANE
Peculiarities of criminal character; some of them are normal and not morbid; their inheritance as in the Jukes family; epileptics and their nervous instability; insanity; religious rapture; strange views of the insane on individuality; their moody segregation; the religious discipline of celibacy, fasting and solitude (see also 125); large field of study among the insane and idiotic.
GREGARIOUS AND SLAVISH INSTINCTS
Most men shrink from responsibility; study of gregarious animals: especially of the cattle of the Damaras; fore-oxen to waggon teams; conditions of safety of herds; cow and young calf when approached by lions; the most effective size of herd; corresponding production of leaders; similarly as regards barbarian tribes and their leaders; power of tyranny vested in chiefs; political and religious persecutions; hence human servility; but society may flourish without servility; its corporate actions would then have statistical constancy; nations who are guided by successive orators, etc., must be inconstant; the romantic side of servility; free political life.
Reference to _Hereditary Genius_.
Purport of inquiry; circular of questions (see Appendix for this); the first answers were from scientific men, and were negative; those from persons in general society were quite the reverse; sources of my materials; they are mutually corroborative. Analysis of returns from 100 persons mostly of some eminence; extracts from replies of those in whom the visualising faculty is highest; those in whom it is mediocre; lowest; conformity between these and other sets of haphazard returns; octile, median, etc., values; visualisation of colour; some liability to exaggeration; blindfold chess-players; remarkable instances of visualisation; the faculty is not necessarily connected with keen sight or tendency to dream; comprehensive imagery; the faculty in different sexes and ages; is strongly hereditary; seems notable among the French; Bushmen; Eskimo; prehistoric men; admits of being educated; imagery usually fails in flexibility; special and generic images (see also Appendix); use of the faculty.
General account of the peculiarity; mutually corroborative statements; personal evidence given at the Anthropological Institute; specimens of a few descriptions and illustrative woodcuts; great variety in the Forms; their early origin; directions in which they run; bold conceptions of children concerning height and depth; historical dates, months, etc.; alphabet; derivation of the Forms from the spoken names of numerals; fixity of the Form compared to that of the handwriting; of animals working in constant patterns; of track of eye when searching for lost objects; occasional origin from figures on clock; from various other sources; the non-decimal nomenclature of numerals; perplexity caused by it. Description of figures in Plate I.; Plate II.; Plate III.; Plate IV. Colours assigned to numerals (see 105); personal characters; sex; frequency with which the various numerals are used in the Talmud.
(Description of Plate IV. continued) Associations with numerals; with words and letters; illustrations by Dr. J. Key; the scheme of one seer unintelligible to other seers; mental music, etc.
Sane persons often see visions; the simpler kinds of visions; unconsciousness of seers, at first, of their peculiarity; subsequent dislike to speak about it; imagery connected with words; that of Mrs. Haweis; automatic changes in dark field of eye; my own experiences; those of Rev. G. Henslow; visions frequently unlike vivid visualisations; phantasmagoria; hallucinations; simile of a seal in a pond; dreams and partial sensitiveness of brain; hallucinations and illusions, their causes; “faces in the fire,” etc.; sub-conscious picture-drawing; visions based on patched recollections; on blended recollections; hereditary seership; visions caused by fasting, etc.; by spiritual discipline (see also 47); star of Napoleon I.; hallucinations of great men; seers commoner at some periods than at others; reasons why.
NURTURE AND NATURE
Their effects are difficult to separate; the same character has many phases; Renaissance; changes owing merely to love of change; feminine fashions; periodical sequences of changed character in birds; the interaction of nurture and nature.
Derived from experience; especially from childish recollections (see 141); abstract ideas; cumulative ideas, like composite portraits (see also Appendix, “Generic Images,” p. 229); their resemblance even in details.
Difficulty of watching the mind in operation; how it may be overcome; irksomeness of the process; tentative experiments; method used subsequently; the number of recurrent associations; memory; ages at which associations are formed; similarity of the associations in persons of the same country and class of society; different descriptions of associations,
classified; their relative frequency; abstract ideas are slowly formed; multifariousness of sub-conscious operations.
ANTECHAMBER OF CONSCIOUSNESS
Act of thinking analysed; automatic mental work; fluency of words and of imagery; processes of literary composition; fluency of spiritual ideas; visionary races of men; morbid ideas of inspiration (see Enthusiasm).
Accidents of education, religion, country, etc.; deaf-mutes and religious ritual; religion in its essentials; all religious teachers preach faith and instil prejudices; origin of the faculty of conscience; evolution is always behindhand; good men of various faiths; the fear of death; terror is easily taught; gregarious animals (see also 47); suspiciousness in the children of criminals; Dante and contemporary artists on the terrors of hell; aversion is easily taught, Eastern ideas of clean and unclean acts; the foregoing influences affect entire classes.
HISTORY OF TWINS
It supplies means of comparing the effects of nurture and nature; physiological signification of twinship; replies to a circular of inquiries; eighty cases of close resemblance between twins; the points in which their resemblance was closest; extracts from the replies; interchangeableness of likeness; cases of similar forms of insanity in both twins; their tastes and dispositions; causes of growing dissimilarity mainly referred to illness; partly to gradual development of latent elements of dissimilarity; effect of childish illnesses in permanently checking growth of head; parallel lives and deaths among twins; necessitarianism; twenty cases of great dissimilarity; extracts from the replies; evidence of slight exaggeration; education is almost powerless to diminish natural difference of character; simile of sticks floating down a brook; depth of impressions made in childhood; they are partly due to the ease with which parents and children understand one another; cuckoos forget the teachings of their foster-mothers.
DOMESTICATION OF ANIMALS
Alternative hypotheses of the prehistoric process of domestication; savages rear captive animals; instances in North America; South America; North Africa; Equatorial Africa; South Africa; Australia; New Guinea Group; Polynesia; ancient Syria. Sacred animals; menageries and shows in amphitheatres; instances in ancient Egypt; Assyria; Rome; Mexico; Peru; Syria and Greece. Domestication is only possible when the species has certain natural faculties, viz.–great hardiness; fondness for man; desire of comfort; usefulness to man; fertility; being easy to tend. Habitual selection of the tamest to breed from. Exceptions; summary.
THE OBSERVED ORDER OF EVENTS
Steady improvement in the birthright of successive generations; our ignorance of the origin and purport of all existence; of the outcome of life on this earth; of the conditions of consciousness; slow progress of evolution and its system of ruthless routine; man is the heir of long bygone ages; has great power in expediting the course of evolution; he might render its progress less slow and painful; does not yet understand that it may be his part to do so.
SELECTION AND RACE
Difference between the best specimens of a poor race and the mediocre ones of a high race; typical centres to which races tend to revert; delicacy of highly-bred animals; their diminished fertility; the misery of rigorous selection; it is preferable to replace poor races by better ones; strains of emigrant blood; of exiles.
INFLUENCE OF MAN UPON RACE
Conquest, migrations, etc.; sentiment against extinguishing races; is partly unreasonable; the so-called “aborigines”; on the variety and number of different races inhabiting the same country; as in Spain; history of the Moors; Gypsies; the races in Damara Land; their recent changes; races in Siberia; Africa; America; West Indies; Australia and New Zealand; wide diffusion of Arabs and Chinese; power of man to shape future humanity.
Over-population; Malthus–the danger of applying his prudential check; his originality; his phrase of misery check is in many cases too severe; decaying races and the cause of decay.
EARLY AND LATE MARRIAGES
Estimate of their relative effects on a population in a few generations; example.
MARKS FOR FAMILY MERIT
On the demand for definite proposals how to improve race; the demand is not quite fair, and the reasons why; nevertheless attempt is made to suggest the outline of one; on the signs of superior race; importance of giving weight to them when making selections from candidates who are personally equal; on families that have thriven; that are healthy and long-lived; present rarity of our knowledge concerning family antecedents; Mr. F.M. Hollond on the superior morality of members of large families; Sir William Gull on their superior vigour; claim for importance of further inquiries into the family antecedents of those who succeed in after life; probable large effect of any system by which marks might be conferred on the ground of family merit.
These have frequently been made in order to furnish marriage portions; they, as well as the adoption of gifted children of gifted families, may hereafter become common; college statutes enjoining celibacy on Fellows; reverse effect to that for which prizes at races were established; the recent reform of those statutes and numerous marriages in consequence; the English race has yet to be explored for its natural wealth; those who are naturally gifted would be disinclined to squander their patrimony; social consideration; honest pride in goodness of race.
Epitome of data; the apparent place of man in nature; he should look upon himself as a freeman; he should assist in furthering evolution; his present ability to do so; the certainty that his ability of doing so will increase; importance of life-histories; brief summary.
A. COMPOSITE PORTRAITURE
I. Extract of Memoir read in 1878 before the Anthropological Institute;
II. Generic Images, extract from Lecture in 1879 to Royal Institution;
III. Memoir read in 1881 before the Photographic Society.
B. THE RELATIVE SUPPLIES FROM TOWN AND COUNTRY FAMILIES TO THE POPULATION OF FUTURE GENERATIONS
Memoir read in 1873 before the Statistical Society.
C. AN APPARATUS FOR TESTING THE DELICACY WITH WHICH WEIGHTS CAN BE DISCRIMINATED BY HANDLING THEM
Memoir read in 1882 before the Anthropological Institute.
D. WHISTLES FOR TESTING THE UPPER LIMITS OF AUDIBLE SOUND IN DIFFERENT INDIVIDUALS
Read in 1876 at the South Kensington Conferences in connection with the Loan Exhibition of Scientific Instruments.
E. QUESTIONS ON VISUALISING AND OTHER ALLIED FACULTIES
Circulated in 1880.
SPECIMENS OF COMPOSITE PORTRAITURE
EXAMPLES OF NUMBER-FORMS
EXAMPLES OF NUMBER-FORMS
EXAMPLES OF NUMBER FORMS, HEREDITARY
COLOUR ASSOCIATIONS AND MENTAL IMAGERY
INQUIRIES INTO HUMAN FACULTY
Since the publication of my work on _Hereditary Genius_ in 1869, I have written numerous memoirs, of which a list is given in an earlier page, and which are scattered in various publications. They may have appeared desultory when read in the order in which they appeared, but as they had an underlying connection it seems worth while to bring their substance together in logical sequence into a single volume. I have revised, condensed, largely re-written, transposed old matter, and interpolated much that is new; but traces of the fragmentary origin of the work still remain, and I do not regret them. They serve to show that the book is intended to be suggestive, and renounces all claim to be encyclopedic. I have indeed, with that object, avoided going into details in not a few cases where I should otherwise have written with fulness, especially in the Anthropometric part. My general object has been to take note of the varied hereditary faculties of different men, and of the great differences in different families and races, to learn how far history may have shown the practicability of supplanting inefficient human stock by better strains, and to consider whether it might not be our duty to do so by such efforts as may be reasonable, thus exerting ourselves to further the ends of evolution more rapidly and with less distress than if events were left to their own course. The subject is, however, so entangled with collateral considerations that a straightforward step-by-step inquiry did not seem to be the most suitable course. I thought it safer to proceed like the surveyor of a new country, and endeavour to fix in the first instance as truly as I could the position of several cardinal points. The general outline of the results to which I finally arrived became more coherent and clear as this process went on; they are brieflv summarised in the concluding chapter.
VARIETY OF HUMAN NATURE.
We must free our minds of a great deal of prejudice before we can rightly judge of the direction in which different races need to be improved. We must be on our guard against taking our own instincts of what is best and most seemly, as a criterion for the rest of mankind. The instincts and faculties of different men and races differ in a variety of ways almost as profoundly as those of animals in different cages of the Zoological Gardens; and however diverse and antagonistic they are, each may be good of its kind. It is obviously so in brutes; the monkey may have a horror at the sight of a snake, and a repugnance to its ways, but a snake is just as perfect an animal as a monkey. The living world does not consist of a repetition of similar elements, but of an endless variety of them, that have grown, body and soul, through selective influences into close adaptation to their contemporaries, and to the physical circumstances of the localities they inhabit. The moral and intellectual wealth of a nation largely consists in the multifarious variety of the gifts of the men who compose it, and it would be the very reverse of improvement to make all its members assimilate to a common type. However, in every race of domesticated animals, and especially in the rapidly-changing race of man, there are elements, some ancestral and others the result of degeneration, that are of little or no value, or are positively harmful. We may, of course, be mistaken about some few of these, and shall find in our fuller knowledge that they subserve the public good in some indirect manner; but, notwithstanding this possibility, we are justified in roundly asserting that the natural characteristics of every human race admit of large improvement in many directions easy to specify.
I do not, however, offer a list of these, but shall confine myself to directing attention to a very few hereditary characteristics of a marked kind, some of which are most desirable and others greatly the reverse; I shall also describe new methods of appraising and defining them. Later on in the book I shall endeavour to define the place and duty of man in the furtherance of the great scheme of evolution, and I shall show that he has already not only adapted circumstance to race, but also, in some degree and often unconsciously, race to circumstance; and that his unused powers in the latter direction are more considerable than might have been thought.
It is with the innate moral and intellectual faculties that the book is chiefly concerned, but they are so closely bound up with the physical ones that these must be considered as well. It is, moreover, convenient to take them the first, so I will begin with the features.
The differences in human features must be reckoned great, inasmuch as they enable us to distinguish a single known face among those of thousands of strangers, though they are mostly too minute for measurement. At the same time, they are exceedingly numerous. The general expression of a face is the sum of a multitude of small details, which are viewed in such rapid succession that we seem to perceive them all at a single glance. If any one of them disagrees with the recollected traits of a known face, the eye is quick at observing it, and it dwells upon the difference. One small discordance overweighs a multitude of similarities and suggests a general unlikeness; just as a single syllable in a sentence pronounced with a foreign accent makes one cease to look upon the speaker as a countryman. If the first rough sketch of a portrait be correct so far as it goes, it may be pronounced an excellent likeness; but a rough sketch does not go far; it contains but few traits for comparison with the original. It is a suggestion, not a likeness; it must be coloured and shaded with many touches before it can really resemble the face, and whilst this is being done the maintenance of the likeness is imperilled at every step. I lately watched an able artist painting a portrait, and endeavoured to estimate the number of strokes with his brush, every one of which was thoughtfully and firmly given. During fifteen sittings of three working hours each–that is to say, during forty-five hours, or two thousand four hundred minutes–he worked at the average rate of ten strokes of the brush per minute. There were, therefore, twenty-four thousand separate traits in the completed portrait, and in his opinion some, I do not say equal, but comparably large number of units of resemblance with the original.
The physiognomical difference between different men being so numerous and small, it is impossible to measure and compare them each to each, and to discover by ordinary statistical methods the true physiognomy of a race. The usual way is to select individuals who are judged to be representatives of the prevalent type, and to photograph them; but this method is not trustworthy, because the judgment itself is fallacious. It is swayed by exceptional and grotesque features more than by ordinary ones, and the portraits supposed to be typical are likely to be caricatures. One fine Sunday afternoon I sat with a friend by the walk in Kensington Gardens that leads to the bridge, and which on such occasions is thronged by promenaders. It was agreed between us that whichever first caught sight of a typical John Bull should call the attention of the other. We sat and watched keenly for many minutes, but neither of us found occasion to utter a word.
The prevalent type of English face has greatly changed at different periods, for after making large allowance for the fashion in portrait painting of the day, there remains a great difference between the proportion in which certain casts of features are to be met with at different dates. I have spent some time in studying the photographs of the various portraits of English worthies that have been exhibited at successive loan collections, or which are now in the National Portrait Gallery, and have traced what appear to be indisputable signs of one predominant type of face supplanting another. For instance, the features of the men painted by and about the time of Holbein have usually high cheekbones, long upper lips, thin eyebrows, and lank dark hair. It would be impossible, I think, for the majority of modern Englishmen so to dress themselves and clip and arrange their hair, as to look like the majority of these portraits.
Englishmen are now a fair and reddish race, as may be seen from the Diagram, taken from the Report of the Anthropometric Committee to the British Association in 1880 and which gives the proportion in which the various colours of hair are found among our professional classes.
I take the professional classes because they correspond with the class of English worthies better than any of the others from which returns have been collected. The Diagram, however, gives a fair representation of other classes of the community. For instance, I have analysed the official records of the very carefully-selected crews of H.M. S. _Alert_ and _Discovery_ in the Arctic Expedition of 1875-6, and find the proportion of various shades of hair to be the same among them as is shown in the Diagram. Seven-tenths of the crews had complexions described as light, fair, fresh, ruddy or freckled, and the same proportion had blue or gray eyes. They would have contrasted strongly with Cromwell’s regiment of Ironsides, who were recruited from the dark-haired men of the fen districts, and who are said to have left the impression on contemporary observers as being men of a peculiar breed. They would also probably have contrasted with any body of thoroughgoing Puritan soldiers taken at haphazard; for there is a prevalence of dark hair among men of atrabilious and sour temperament.
If we may believe caricaturists, the fleshiness and obesity of many English men and women in the earlier years of this century must have been prodigious. It testifies to the grosser conditions of life in those days, and makes it improbable that the types best adapted to prevail then would be the best adapted to prevail now.
As a means of getting over the difficulty of procuring really representative faces, I contrived the method of composite portraiture, which has been explained of late on many occasions, and of which a full account will be found in Appendix A. The principle on which the composites are made will best be understood by a description of my earlier and now discarded method; it was this–(1) I collected photographic portraits of different persons, all of whom had been photographed in the same aspect (say full face), and under the same conditions of light and shade (say with the light coming from the right side). (2) I reduced their portraits photographically to the same size, being guided as to scale by the distance between any two convenient points of reference in the features; for example, by the vertical distance between two parallel lines, one of which passed through the middle of the pupils of the eyes and the other between the lips. (3) I superimposed the portraits like the successive leaves of a book, so that the features of each portrait lay as exactly as the case admitted, in front of those of the one behind it, eye in front of eye and mouth in front of mouth. This I did by holding them successively to the light and adjusting them, then by fastening each to the preceding one with a strip of gummed paper along one of the edges. Thus I obtained a book, each page of which contained a separate portrait, and all the portraits lay exactly in front of one another. (4) I fastened the book against the wall in such a way that I could turn over the pages in succession, leaving in turn each portrait flat and fully exposed. (5) I focused my camera on the book fixed it firmly, and put a sensitive plate inside it. (6) I began photographing, taking one page after the other in succession without moving the camera, but putting on the cap whilst I was turning over the pages, so that an image of each of the portraits in succession was thrown on the same part of the sensitised plate.
Only a fraction of the exposure required to make a good picture was allowed to each portrait. Suppose that period was twenty seconds, and that there were ten portraits, then an exposure of two seconds would be allowed for each portrait, making twenty seconds in all. This is the principle of the process, the details of that which I now use are different and complex. They are fully explained in the Appendix for the use of those who may care to know about them.
The effect of composite portraiture is to bring into evidence all the traits in which there is agreement, and to leave but a ghost of a trace of individual peculiarities. There are so many traits in common in all faces that the composite picture when made from many components is far from being a blur; it has altogether the look of an ideal composition.
It may be worth mentioning that when I take any small bundle of portraits, selected at hazard, I have generally found it easy to sort them into about five groups, four of which have enough resemblance among themselves to make as many fairly clear composites, while the fifth consists of faces that are too incongruous to be grouped in a single class. In dealing with portraits of brothers and sisters, I can generally throw most of them into a single group, with success.
In the small collection of composites given in the Plate facing p. 8, I have purposely selected many of those that I have previously published, and whose originals, on a larger scale, I have at various times exhibited, together with their components, in order to put the genuineness of the results beyond doubt. Those who see them for the first time can hardly believe but that one dominant face has overpowered the rest, and that they are composites only in name. When, however, the details are examined, this objection disappears. It is true that with careless photography one face may be allowed to dominate, but with the care that ought to be taken, and with the precautions described in the Appendix, that does not occur. I have often been amused when showing composites and their components to friends, to hear a strong expression of opinion that the predominance of one face was evident, and then on asking which face it was, to discover that they disagreed. I have even known a composite in which one portrait seemed unduly to prevail, to be remade without the component in question, and the result to be much the same as before, showing that the reason of the resemblance was that the rejected portrait had a close approximation to the ideal average picture of the rest.
These small composites give a better notion of the utmost capacity of the process than the larger ones, from which they are reduced. In the latter, the ghosts of individual peculiarities are more visible, and usually the equal traces left by every member of a moderately-sized group can be made out by careful inspection; but it is hardly possible to do this in the pictures in the Plate, except in a good light and in a very few of the cases. On the other hand, the larger pictures do not contain more detail of value than the smaller ones.
DESCRIPTION OF THE COMPOSITES.
The medallion of Alexander the Great was made by combining the images of six different medals, with a view of obtaining the type of features that the makers of those medals concurred in desiring to ascribe to him. The originals were kindly selected for me by Mr. R. Stuart Poole from the collection in the British Museum. This composite was one of the first I ever made, and is printed together with its six components in the _Journal of the Royal Institution_, in illustration of a lecture I gave there in April 1879. It seems to me that it is possible on this principle to obtain a truer likeness of a man than in any other way. Every artist makes mistakes; but by combining the conscientious works of many artists, their separate mistakes disappear, and what is common to all of their works remains. So as regards different photographs of the same person, those accidental momentary expressions are got rid of, which an ordinary photograph made by a brief exposure cannot help recording. On the other hand, any happy sudden trait of expression is lost. The composite gives the features in repose.
The next pair of composites (full face and profile) on the Plate has not been published before. The interest of the pair lies chiefly in their having been made from only two components, and they show how curiously even two faces that have a moderate family likeness will blend into a single one. That neither of these predominated in the present case will be learned from the following letter by the father of the ladies, who is himself a photographer:–
“I am exceedingly obliged for the very curious and interesting composite portraits of my two children. Knowing the faces so well, it caused me quite a surprise when I opened your letter. I put one of the full faces on the table for the mother to pick up casually. She said, ‘When did you do this portrait of A? how _like_ she is to B! Or _is_ it B? I never thought they were so like before.’ It has puzzled several people to say whether the profile was intended for A or B. Then I tried one of them on a friend who has not seen the girls for years. He said, ‘Well, it is one of the family for certain, but I don’t know which.'”
I have made several other family portraits, which to my eye seem great successes, but must candidly own that the persons whose portraits are blended together seldom seem to care much for the result, except as a curiosity. We are all inclined to assert our individuality, and to stand on our own basis, and to object to being mixed up indiscriminately with others. The same feeling finds expression when the resident in a suburban street insists on calling his house a villa with some fantastic name, and refuses, so long as he can, to call it simply Number so and so in the street.
The last picture in the upper row shows the easy way in which young and old, male and female, combine to form an effective picture. The components consist in this case of the father and mother, two sons, and two daughters. I exhibited the original of this, together with the portraits from which it was taken, at the Loan Photographic Exhibition at the Society of Arts in February 1882. I also sent copies of the original of this same composite to several amateur photographers, with a circular letter asking them to get from me family groups for the purpose of experiments, to see how far the process was suitable for family portraiture.
The middle row of portraits illustrates health, disease, and criminality. For health, I have combined the portraits of twelve officers of the Royal Engineers with about an equal number of privates, which were taken for me by Lieutenant Darwin, R.E. The individuals from whom this composite was made, which has not come out as clearly as I should have liked, differed considerably in feature, and they came from various parts of England. The points they had in common were the bodily and mental qualifications required for admission into their select corps, and their generally British descent. The result is a composite having an expression of considerable vigour, resolution, intelligence, and frankness. I have exhibited both this and others that were made respectively from the officers, from the whole collection of privates–thirty-six in number–and from that selected portion of them that is utilised in the present instance.
This face and the qualities it connotes probably gives a clue to the direction in which the stock of the English race might most easily be improved. It is the essential notion of a race that there should be some ideal typical form from which the individuals may deviate in all directions, but about which they chiefly cluster, and towards which their descendants will continue to cluster. The easiest direction in which a race can be improved is towards that central type, because nothing new has to be sought out. It is only necessary to encourage as far as practicable the breed of those who conform most nearly to the central type, and to restrain as far as may be the breed of those who deviate widely from it. Now there can hardly be a more appropriate method of discovering the central physiognomical type of any race or group than that of composite portraiture.
As a contrast to the composite of the Royal Engineers, I give those of two of the coarse and low types of face found among the criminal classes. The photographs from which they were made are taken from two large groups. One are those of men undergoing severe sentences for murder and other crimes connected with violence; the other of thieves. They were reprints from those taken by order of the prison authorities for purposes of identification. I was allowed to obtain copies for use in my inquiries by the kind permission of Sir Edmund Du Cane, H.M. Director of Prisons. The originals of these and their components have frequently been exhibited. It is unhappily a fact that fairly distinct types of criminals breeding true to their kind have become established, and are one of the saddest disfigurements of modern civilisation. To this subject I shall recur.
I have made numerous composites of various groups of convicts, which are interesting negatively rather than positively. They produce faces of a mean description, with no villainy written on them. The individual faces are villainous enough, but they are villainous in different ways, and when they are combined, the individual peculiarities disappear, and the common humanity of a low type is all that is left.
The remaining portraits are illustrations of the application of the process to the study of the physiognomy of disease. They were published a year ago with many others, together with several of the portraits from which they were derived, in a joint memoir by Dr. Mahomed and myself, in vol. xxv. of the _Guy’s Hospital Reports_. The originals and all the components have been exhibited on several occasions.
In the lower division of the Plate will be found three composites, each made from a large number of faces, unselected, except on the ground of the disease under which they were suffering. When only few portraits are used, there must be some moderate resemblance between them, or the result would be blurred; but here, dealing with as many as 56, 100, and 50 cases respectively, the combination of any medley group results in an ideal expression.
It will be observed that the composite of 56 female faces is made by the blending of two other composites, both of which are given. The history was this–I took the 56 portraits and sorted them into two groups; in the first of these were 20 portraits that showed a tendency to thin features, in the other group there were 36 that showed a tendency to thickened features. I made composites of each of them as shown in the Plate. Now it will be remarked that, notwithstanding the attempt to make two contrasted groups, the number of mediocre cases was so great that the composities of the two groups are much alike. If I had divided the 56 into two haphazard groups, the results would have been closely alike, as I know from abundant experience of the kind. The co-composite of the two will be observed to have an intermediate expression. The test and measure of statistical truth lies in the degree of accordance between results obtained from different batches of instances of the same generic class. It will be gathered from these instances that composite portraiture may attain statistical constancy, within limits not easily distinguished by the eye, after some 30 haphazard portraits of the same class have been combined. This at least has been my experience thus far.
The two faces illustrative of the same type of tubercular disease are very striking; the uppermost is photographically interesting as a case of predominance of one peculiarity, happily of no harm to the effect of the ideal wan face. It is that one of the patients had a sharply-checked black and white scarf, whose pattern has asserted itself unduly in the composite. In such cases I ought to throw the too clearly defined picture a little out of focus. The way in which the varying brightness of different pictures is reduced to a uniform standard of illumination is described in the Appendix.
It must be clearly understood that these portraits do not profess to give the whole story of the physiognomy of phthisis. I have not room to give illustrations of other types–namely, that with coarse and blunted features, or the strumous one, nor any of the intermediates. These have been discussed chiefly by Dr. Mahomed in the memoir alluded to above.
In the large experience I have had of sorting photographs, literally by the thousand, while making experiments with composites, I have been struck by certain general impressions. The consumptive patients consisted of many hundred cases, including a considerable proportion of very ignoble specimens of humanity. Some were scrofulous and misshapen, or suffered from various loathsome forms of inherited disease; most were ill nourished. Nevertheless, in studying their portraits the pathetic interest prevailed, and I returned day after day to my tedious work of classification, with a liking for my materials. It was quite otherwise with the criminals. I did not adequately appreciate the degradation of their expressions for some time; at last the sense of it took firm hold of me, and I cannot now handle the portraits without overcoming by an effort the aversion they suggest.
I am sure that the method of composite portraiture opens a fertile field of research to ethnologists, but I find it very difficult to do much single-handed, on account of the difficulty of obtaining the necessary materials. As a rule, the individuals must be specially photographed. The portraits made by artists are taken in every conceivable aspect and variety of light and shade, but for the purpose in question the aspect and the shade must be the same throughout. Group portraits would do to work from, were it not for the strong out-of-door light under which they are necessarily taken, which gives an unwonted effect to the expression of the faces. Their scale also is too small to give a sufficiently clear picture when enlarged. I may say that the scale of the portraits need not be uniform, as my apparatus enlarges or reduces as required, at the same time that it superposes the images; but the portraits of the heads should never be less than twice the size of that of the Queen on a halfpenny piece.
I heartily wish that amateur photographers would seriously take up the subject of composite portraiture as applied to different sub-types of the varying races of men. I have already given more time to perfecting the process and experimenting with it than I can well spare.
The differences in the bodily qualities that are the usual subjects of anthropometry are easily dealt with, and are becoming widely registered in many countries. We are unfortunately destitute of trustworthy measurements of Englishmen of past generations to enable us to compare class with class, and to learn how far the several sections of the English nation may be improving or deteriorating. We shall, however, hand useful information concerning our own times to our successors, thanks principally to the exertions of an Anthropometric Committee established five years ago by the British Association, who have collected and partly classified and published a large amount of facts, besides having induced several institutions, such as Marlborough College, to undertake a regular system of anthropometric record. I am not, however, concerned here with the labours of this committee, nor with the separate valuable publications of some of its members, otherwise than in one small particular which appears to show that the English population as a whole, or perhaps I should say the urban portion of it, is in some sense deteriorating. It is that the average stature of the older persons measured by or for the committee has not been found to decrease steadily with their age, but sometimes the reverse. This contradicts observations made on the heights of the same men at different periods, whose stature after middle age is invariably reduced by the shrinking of the cartilages. The explanation offered was that the statistical increase of stature with age should be ascribed to the survival of the more stalwart. On reconsideration, I am inclined to doubt the adequacy of the explanation, and partly to account for the fact by a steady, slight deterioration of stature in successive years; in the urban population owing to the conditions of their lives, and in the rural population owing to the continual draining away of the more stalwart of them to the towns.
It cannot be doubted that town life is harmful to the town population. I have myself investigated its effect on fertility (see Appendix B), and found that taking on the one hand a number of rural parishes, and on the other hand the inhabitants of a medium town, the former reared, nearly twice as many adult grandchildren as the latter. The vital functions are so closely related that an inferiority in the production of healthy children very probably implies a loss of vigour generally, one sign of which is a diminution of stature.
Though the bulk of the population may deteriorate, there are many signs that the better housed and fed portion of it improves. In the earlier years of this century the so-called manly sports of boxing and other feats of strength ranked high among the national amusements. A man who was  successful in these became the hero of a large and demonstrative circle of admirers, and it is to be presumed that the best boxer, the best pedestrian, and so forth, was the best adapted to succeed, through his natural physical gifts. If he was not the most gifted man in those respects in the whole kingdom, he was certainly one of the most gifted of them. It therefore does no injustice to the men of that generation to compare the feats of their foremost athletes with those of ours who occupy themselves in the same way. The comparison would probably err in their favour, because the interest in the particular feats in which our grandfathers and great-grandfathers delighted are not those that chiefly interest the present generation, and notwithstanding our increased population, there are fewer men now who attempt them. In the beginning of this century there were many famous walking matches, and incomparably the best walker was Captain Barclay of Ury. His paramount feat, which was once very familiar to the elderly men of the present time, was that of walking a thousand miles in a thousand hours, but of late years that feat has been frequently equalled and overpassed. I am willing to allow much influence to the modern conditions of walking under shelter and subject to improved methods of training (Captain Barclay himself originated the first method, which has been greatly improved since his time); still the fact remains that in executing this particular feat, the athletes of the present day are more successful than those who lived some eighty years ago. I may be permitted to give an example bearing on the increased stature of the better housed and fed portion of the nation, in a recollection of my own as to the difference in height between myself and my fellow-collegians at Trinity College, Cambridge, in 1840-4. My height is 5 feet 9-3/4 inches, and I recollect perfectly that among the crowd of undergraduates I stood somewhat taller than the majority. I generally looked a little downward when I met their eyes. In later years, whenever I have visited Cambridge, I have lingered in the ante-chapel and repeated the comparison, and now I find myself decidedly shorter than the average of the students. I have precisely the same kind of recollection and the same present experience of the height of crowds of well-dressed persons. I used always to get a fair view of what was going on over or between their heads; I rarely can do so now.
[Footnote 1: _Trans. Brit. Assoc_., 1881, Table V., p. 242; and remarks by Mr. Roberts, p. 235.]
The athletic achievements at school and college are much superior to what they used to be. Part is no doubt due to more skilful methods of execution, but not all. I cannot doubt that the more wholesome and abundant food, the moderation in drink, the better cooking, the warmer wearing apparel, the airier sleeping rooms, the greater cleanliness, the more complete change in holidays, and the healthier lives led by the women in their girlhood, who become mothers afterwards, have a great influence for good on the favoured portion of our race.
The proportion of weakly and misshapen individuals is not to be estimated by those whom we meet in the streets; the worst cases are out of sight. We should parade before our mind’s eye the inmates of the lunatic, idiot, and pauper asylums, the prisoners, the patients in hospitals, the sufferers at home, the crippled, and the congenitally blind, and that large class of more or less wealthy persons who flee to the sunnier coasts of England, or expatriate themselves for the chance of life. There can hardly be a sadder sight than the crowd of delicate English men and women with narrow chests and weak chins, scrofulous, and otherwise gravely affected, who are to be found in some of these places. Even this does not tell the whole of the story; if there were a conscription in England, we should find, as in other countries, that a large fraction of the men who earn their living by sedentary occupations are unfit for military service. Our human civilised stock is far more weakly through congenital imperfection than that of any other species of animals, whether wild or domestic.
It is, however, by no means the most shapely or the biggest personages who endure hardship the best. Some very shabby-looking men have extraordinary stamina. Sickly-looking and puny residents in towns may have a more suitable constitution for the special conditions of their lives, and may in some sense be better knit and do more work and live longer than much haler men imported to the same locality from elsewhere. A wheel and a barrel seem to have the flimsiest possible constitutions; they consist of numerous separate pieces all oddly shaped, which, when lying in a heap, look hopelessly unfitted for union; but put them properly together, compress them with a tire in the one case and with hoops in the other, and a remarkably enduring organisation will result. A wheel with a ton weight on the top of it in the waggons of South Africa will jolt for thousands of miles over stony, roadless country without suffering harm; a keg of water may be strapped on the back of a pack-ox or a mule, and be kicked off and trampled on, and be otherwise misused for years, without giving way.
I do not propose to enter further into the anthropometric differences of race, for the subject is a very large one, and this book does not profess to go into detail. Its intention is to touch on various topics more or less connected with that of the cultivation of race, or, as we might call it, with “eugenic”  questions, and to present the results of several of my own separate investigations.
Energy is the capacity for labour. It is consistent with all the robust virtues, and makes a large practice of them possible. It is the measure of fulness of life; the more energy the more abundance of it; no energy at all is death; idiots are feeble and listless. In the inquiries I made on the antecedents of men of science no points came out more strongly than that the leaders of scientific thought were generally gifted with remarkable energy, and that they had  inherited the gift of it from their parents and grandparents. I have since found the same to be the case in other careers.
[Footnote 2: That is, with questions bearing on what is termed in Greek, _eugenes_, namely, good in stock, hereditarily endowed with noble qualities. This, and the allied words, _eugeneia_, etc., are equally applicable to men, brutes, and plants. We greatly want a brief word to express the science of improving stock, which is by no means confined to questions of judicious mating, but which, especially in the case of man, takes cognisance of all influences that tend in however remote a degree to give to the more suitable races or strains of blood a better chance of prevailing speedily over the less suitable than they otherwise would have had. The word _eugenics_ would sufficiently express the idea; it is at least a neater word and a more generalised one than _viriculture_, which I once ventured to use.]
Energy is an attribute of the higher races, being favoured beyond all other qualities by natural selection. We are goaded into activity by the conditions and struggles of life. They afford stimuli that oppress and worry the weakly, who complain and bewail, and it may be succumb to them, but which the energetic man welcomes with a good-humoured shrug, and is the better for in the end.
The stimuli may be of any description: the only important matter is that all the faculties should be kept working to prevent their perishing by disuse. If the faculties are few, very simple stimuli will suffice. Even that of fleas will go a long way. A dog is continually scratching himself, and a bird pluming itself, whenever they are not occupied with food, hunting, fighting, or love. In those blank times there is very little for them to attend to besides their varied cutaneous irritations. It is a matter of observation that well washed and combed domestic pets grow dull; they miss the stimulus of fleas. If animals did not prosper through the agency of their insect plagues, it seems probable that their races would long since have been so modified that their bodies should have ceased to afford a pasture-ground for parasites.
It does not seem to follow that because men are capable of doing hard work they like it. Some, indeed, fidget and fret if they cannot otherwise work off their superfluous steam; but on the other hand there are many big lazy fellows who will not get up their steam to full pressure except under compulsion. Again, the character of the stimulus that induces hard work differs greatly in different persons; it may be wealth, ambition, or other object of passion. The solitary hard workers, under no encouragement or compulsion except their sense of duty to their generation, are unfortunately still rare among us.
It may be objected that if the race were too healthy and energetic there would be insufficient call for the exercise of the pitying and self-denying virtues, and the character of men would grow harder in consequence. But it does not seem reasonable to preserve sickly breeds for the sole purpose of tending them, as the breed of foxes is preserved solely for sport and its attendant advantages. There is little fear that misery will ever cease from the land, or that the compassionate will fail to find objects for their compassion; but at present the supply vastly exceeds the demand: the land is overstocked and overburdened with the listless and the incapable.
In any scheme of eugenics, energy is the most important quality to favour; it is, as we have seen, the basis of living action, and it is eminently transmissible by descent.
The only information that reaches us concerning outward events appears to pass through the avenue of our senses; and the more perceptive the senses are of difference, the larger is the field upon which our judgment and intelligence can act. Sensation mounts through a series of grades of “just perceptible differences.” It starts from the zero of consciousness, and it becomes more intense as the stimulus increases (though at a slower rate) up to the point when the stimulus is so strong as to begin to damage the nerve apparatus. It then yields place to pain, which is another form of sensation, and which continues until the nerve apparatus is destroyed. Two persons may be equally able just to hear the same faint sound, and they may equally begin to be pained by the same loud sound, and yet they may differ as to the number of intermediate grades of sensation. The grades will be less numerous as the organisation is of a lower order, and the keenest sensation possible to it will in consequence be less intense. An artist who is capable of discriminating more differences of tint than another man is not necessarily more capable of seeing clearly in twilight, or more or less intolerant of sunshine. A musician is not necessarily able to hear very faint sounds, nor to be more startled by loud sounds than others are. A mechanic who works hard with heavy tools and has rough and grimy thumbs, insensible to very slight pressures, may yet have a singularly discriminating power of touch in respect to the pressures that he can feel.
The discriminative faculty of idiots is curiously low; they hardly distinguish between heat and cold, and their sense of pain is so obtuse that some of the more idiotic seem hardly to know what it is. In their dull lives, such pain as can be excited in them may literally be accepted with a welcome surprise. During a visit to Earlswood Asylum I saw two boys whose toe-nails had grown into the flesh and had been excised by the surgeon. This is a horrible torture to ordinary persons, but the idiot lads were said to have shown no distress during the operation; it was not necessary to hold them, and they looked rather interested at what was being done.  I also saw a boy with the scar of a severe wound on his wrist; the story being that he had first burned himself slightly by accident, and, liking the keenness of the new sensation, he took the next opportunity of repeating the experience, but, idiot-like, he overdid it.
The trials I have as yet made on the sensitivity of different persons confirms the reasonable expectation that it would on the whole be highest among the intellectually ablest. At first, owing to my confusing the quality of which I am speaking with that of nervous irritability, I fancied that women of delicate nerves who are distressed by noise, sunshine, etc., would have acute powers of discrimination. But this I found not to be the case. In morbidly sensitive persons both pain and sensation are induced by lower stimuli than in the healthy, but the number of just perceptible grades of sensation between them is not necessarily different.
I found as a rule that men have more delicate powers of discrimination than women, and the business experience of life seems to confirm this view. The tuners of pianofortes are men, and so I understand are the tasters of tea and wine, the sorters of wool, and the like. These latter occupations are well salaried, because it is of the first moment to the merchant that he should be rightly advised on the real value of what he is about to purchase or to sell. If the sensitivity of women were superior to that of men, the self-interest of merchants would lead to their being  always employed; but as the reverse is the case, the opposite supposition is likely to be the true one.
[Footnote 3: See “Remarks on Idiocy,” by E.W. Graham, M. D., _Medical Journal_, January 16, 1875.]
Ladies rarely distinguish the merits of wine at the dinner-table, and though custom allows them to preside at the breakfast-table, men think them on the whole to be far from successful makers of tea and coffee.
Blind persons are reputed to have acquired in compensation for the loss of their eyesight an increased acuteness in their other senses; I was therefore curious to make some trials with my test apparatus, which I will describe in the next chapter. I was permitted to do so on a number of boys at a large educational blind asylum, but found that, although they were anxious to do their best, their performances were by no means superior to those of other boys. It so happened that the blind lads who showed the most delicacy of touch and won the little prizes I offered to excite emulation, barely reached the mediocrity of the various sighted lads of the same age whom I had previously tested. I have made not a few observations and inquiries, and find that the guidance of the blind depends mainly on the multitude of collateral indications to which they give much heed, and not in their superior sensitivity to any one of them. Those who see do not care for so many of these collateral indications, and habitually overlook and neglect several of them. I am convinced also that not a little of the popular belief concerning the sensitivity of the blind is due to exaggerated claims on their part that have not been verified. Two instances of this have fallen within my own experience, in both of which the blind persons claimed to have the power of judging by the echo of their voice and by certain other feelings, the one when they were approaching objects, even though the object was so small as a handrail, and the other to tell how far the door of the room in which he was standing was open. I used all the persuasion I could to induce each of these persons to allow me to put their assertions to the test; but it was of no use. The one made excuses, the other positively refused. They had probably the same tendency that others would have who happened to be defective in any faculty that their comrades possessed, to fight bravely against their disadvantage, and at the same time to be betrayed into some overvaunting of their capacities in other directions. They would be a little conscious of this, and would therefore shrink from being tested.
The power of reading by touch is not so very wonderful. A former Lord Chancellor of England, the late Lord Hatherley, when he was advanced in years, lost his eyesight for some time owing to a cataract, which was not ripe to be operated on. He assured me that he had then learned and practised reading by touch very rapidly. This fact may perhaps also serve as additional evidence of the sensitivity of able men.
Notwithstanding many travellers’ tales, I have thus far been unsuccessful in obtaining satisfactory evidence of any general large superiority of the senses of savages over those of civilised men. My own experience, so far as it goes, of Hottentots, Damaras, and some other wild races, went to show that their sense discrimination was not superior to those of white men, even as regards keenness of eyesight. An offhand observer is apt to err by assigning to a single cause what is partly due to others as well. Thus, as regards eyesight, a savage who is accustomed to watch oxen grazing at a distance becomes so familiar with their appearance and habits that he can identify particular animals and draw conclusions as to what they are doing with an accuracy that may seem to strangers to be wholly dependent on exceptional acuteness of vision. A sailor has the reputation of keen sight because he sees a distant coast when a landsman cannot make it out; the fact being that the landsman usually expects a different appearance to what he has really to look for, such as a very minute and sharp outline instead of a large, faint blur. In a short time a landsman becomes quite as quick as a sailor, and in some test experiments he was found on the average to be distinctly the superior. It is not surprising that this should be so, as sailors in vessels of moderate size have hardly ever the practice of focussing their eyes sharply upon objects farther off than the length of the vessel or the top of the mast, say at a distance of fifty paces. The horizon itself as seen from the deck,  and under the most favourable circumstances, is barely four miles off, and there is no sharpness of outline in the intervening waves. Besides this, the life of a sailor is very unhealthy, as shown by his growing old prematurely, and his eyes must be much tried by foul weather and salt spray.
[Footnote 4: Gould’s _Military and Anthropological Statistics_, p. 530. New York, 1869.]
We inherit our language from barbarous ancestors, and it shows traces of its origin in the imperfect ways by which grades of difference admit of being expressed. Suppose a pedestrian is asked whether the knapsack on his back feels heavy. He cannot find a reply in two words that cover more varieties than (1) very heavy, (2) rather heavy, (3) moderate, (4) rather light, (5) very light. I once took considerable pains in the attempt to draw up verbal scales of more than five orders of magnitude, using those expressions only that every cultivated person would understand in the same sense; but I did not succeed. A series that satisfied one person was not interpreted in the same sense by another.
The general intention of this chapter has been to show that a delicate power of sense discrimination is an attribute of a high race, and that it has not the drawback of being necessarily associated with nervous irritability.
SEQUENCE OF TEST WEIGHTS.
I will now describe an apparatus I have constructed to test the delicacy with which weights may be discriminated by handling them. I do so because the principle on which it is based may be adopted in apparatus for testing other senses, and its description and the conditions of its use will illustrate the desiderata and difficulties of all such investigations.
A series of test weights is a simple enough idea–the difficulty lies in determining the particular sequence of weights that should be employed. Mine form a geometric series, for the reason that when stimuli of all kinds increase by geometric grades the sensations they give rise to will increase by arithmetic grades, so long as the stimulus is neither so weak as to be barely felt, nor so strong as to excite fatigue. My apparatus, which is explained more fully in the Appendix, consists of a number of common gun cartridge cases filled with alternate layers of shot, wool, and wadding, and then closed in the usual way. They are all identical in appearance, and may be said to differ only in their specific gravities. They are marked in numerical sequence with the register numbers, 1, 2, 3, etc., but their weights are proportioned to the numbers of which 1, 2, 3, etc., are the logarithms, and consequently run in a geometric series. Hence the numbers of the weights form a scale of equal degrees of sensitivity. If a person can just distinguish between the weights numbered 1 and 3, he can also just distinguish between 2 and 4, 3 and 5, and any other pair of weights of which the register number of the one exceeds that of the other by 2. Again, his coarseness of discrimination is exactly double of that of another person who can just distinguish pairs of weights differing only by 1, such as 1 and 2, 2 and 3, 3 and 4, and so on. The testing is performed by handing pairs of weights to the operatee until his power of discrimination is approximately made out, and then to proceed more carefully. It is best now, for reasons stated in the Appendix, to hand to the operatee sequences of three weights at a time, after shuffling them. These he has to arrange in their proper order, with his eyes shut, and by the sense of their weight alone. The operator finally records the scale interval that the operatee can just appreciate, as being the true measure of the coarseness (or the inverse measure of the delicacy) of the sensitivity of the operatee.
It is somewhat tedious to test many persons in succession, but any one can test his own powers at odd and end times with ease and nicety, if he happens to have ready access to suitable apparatus.
The use of tests, which, objectively speaking, run in a geometric series, and subjectively in an arithmetic one, may be applied to touch, by the use of wire-work of various degrees of fineness; to taste, by stock bottles of solutions of salt, etc., of various strengths; to smell, by bottles of attar of rose, etc., in various degrees of dilution.
The tests show the sensitivity at the time they are made, and give an approximate measure of the discrimination with which the operatee habitually employs his senses. It does not measure his capacity for discrimination, because the discriminative faculty admits of much education, and the test results always show increased delicacy after a little practice. However, the requirements of everyday life educate all our faculties in some degree, and I have not found the performances with test weights to improve much after a little familiarity with their use. The weights have, as it were, to be played with at first, then they must be tried carefully on three or four separate occasions.
I did not at first find it at all an easy matter to make test weights so alike as to differ in no other appreciable respect than in their specific gravity, and if they differ and become known apart, the knowledge so acquired will vitiate future judgments in various indirect ways. Similarity in outward shape and touch was ensured by the use of mechanically-made cartridge cases; dissimilarity through any external stain was rendered of no hindrance to the experiment by making the operatee handle them in a bag or with his eyes shut. Two bodies may, however, be alike in weight and outward appearance and yet behave differently when otherwise mechanically tested, and, consequently, when they are handled. For example, take two eggs, one raw and the other hard boiled, and spin them on the table; press the finger for a moment upon either of them whilst it is still spinning: if it be the hard-boiled egg it will stop as dead as a stone: if it be the raw egg, after a little apparent hesitation, it will begin again to rotate. The motion of its shell had alone been stopped; the internal part was still rotating and this compelled the shell to follow it. Owing to this cause, when we handle the two eggs, the one feels “quick” and the other does not. Similarly with the cartridges, when one is rather more loosely packed than the others the difference is perceived on handling them. Or it may have one end heavier than the other, or else its weight may not be equally distributed round its axis, causing it to rest on the table with the same part always lowermost; differences due to these causes are also easily perceived when handling the cartridges. Again, one of two similar cartridges may balance perfectly in all directions, but the weight of one of them may be disposed too much towards the ends, as in a dumb-bell, or gathered too much towards the centre. The period of oscillation will differ widely in the two cases, as may be shown by suspending the cartridges by strings round their middle so that they shall hang horizontally, and then by a slight tap making them spin to and fro round the string as an axis.
The touch is very keen in distinguishing all these peculiarities. I have mentioned them, and might have added more, to show that experiments on sensitivity have to be made in the midst of pitfalls warily to be avoided. Our apparently simplest perceptions are very complex. We hardly ever act on the information given by only one element of one sense, and our sensitivity in any desired direction cannot be rightly determined except by carefully-devised apparatus judiciously used.
WHISTLES FOR AUDIBILITY OF SHRILL NOTES.
I contrived a small whistle for conveniently ascertaining the upper limits of audible sound in different persons, which Dr. Wollaston had shown to vary considerably. He used small pipes, and found much difficulty in making them. I made a very small whistle from a brass tube whose internal diameter was less than one-tenth of an inch in diameter. A plug was fitted into the lower end of the tube, which could be pulled out or pushed in as much as desired, thereby causing the length of the bore of the whistle to be varied at will. When the bore is long the note is low; when short, it is high. The plug was graduated, so that the precise note produced by the whistle could be determined by reading off the graduations and referring to a table. (See Appendix.)
On testing different persons, I found there was a remarkable falling off in the power of hearing high notes as age advanced. The persons themselves were quite unconscious of their deficiency so long as their sense of hearing low notes remained unimpaired. It is an only too amusing experiment to test a party of persons of various ages, including some rather elderly and self-satisfied personages. They are indignant at being thought deficient in the power of hearing, yet the experiment quickly shows that they are absolutely deaf to shrill notes which the younger persons hear acutely, and they commonly betray much dislike to the discovery. Every one has his limit, and the limit at which sounds become too shrill to be audible to any particular person can be rapidly determined by this little instrument. Lord Rayleigh and others have found that sensitive flames are powerfully affected by the vibrations of whistles that are too rapid to be audible to ordinary ears.
I have tried experiments with all kinds of animals on their powers of hearing shrill notes. I have gone through the whole of the Zoological Gardens, using an apparatus arranged for the purpose. It consists of one of my little whistles at the end of a walking-stick–that is, in reality, a long tube; it has a bit of india-rubber pipe under the handle, a sudden squeeze upon which forces a little air into the whistle and causes it to sound. I hold it as near as is safe to the ears of the animals, and when they are quite accustomed to its presence and heedless of it, I make it sound; then if they prick their ears it shows that they hear the whistle; if they do not, it is probably inaudible to them. Still, it is very possible that in some cases they hear but do not heed the sound. Of all creatures, I have found none superior to cats in the power of hearing shrill sounds; it is perfectly remarkable what a faculty they have in this way. Cats, of course, have to deal in the dark with mice, and to find them out by their squealing. Many people cannot hear the shrill squeal of a mouse. Some time ago, singing mice were exhibited in London, and of the people who went to hear them, some could hear nothing, whilst others could hear a little, and others again could hear much. Cats are differentiated by natural selection until they have a power of hearing all the high notes made by mice and other little creatures that they have to catch. A cat that is at a very considerable distance, can be made to turn its ear round by sounding a note that is too shrill to be audible by almost any human ear. Small dogs also hear very shrill notes, but large ones do not. I have walked through the streets of a town with an instrument like that which I used in the Zoological Gardens, and made nearly all the little dogs turn round, but not the large ones. At Berne, where there appear to be more large dogs lying idly about the streets than in any other town in Europe, I have tried the whistle for hours together, on a great many large dogs, but could not find one that heard it. Ponies are sometimes able to hear very high notes. I once frightened a pony with one of these whistles in the middle of a large field. My attempts on insect hearing have been failures.
When shall we have anthropometric laboratories, where a man may, when he pleases, get himself and his children weighed, measured, and rightly photographed, and have their bodily faculties tested by the best methods known to modern science? The records of growth of numerous persons from childhood to age are required before it can be possible to rightly appraise the effect of external conditions upon development, and records of this kind are at present non-existent. The various measurements should be accompanied by photographic studies of the features in full face and in profile, and on the same scale, for convenience of comparison.
We are all lazy in recording facts bearing on ourselves, but parents are glad enough to do so in respect to their children, and they would probably be inclined to avail themselves of a laboratory where all that is required could be done easily and at small cost. These domestic records would hereafter become of considerable biographical interest. Every one of us in his mature age would be glad of a series of pictures of himself from childhood onwards, accompanied by physical records, and arranged consecutively with notes of current events by their sides. Much more would he be glad of similar collections referring to his father, mother, grandparents, and other near relatives. It would be peculiarly grateful to the young to possess likenesses of their parents and those whom they look upon as heroes, taken when they were of the same age as themselves. Boys are too apt to think of their parents as having always been elderly men, because they have insufficient data to construct imaginary pictures of them as they were in their youth.
The cost of taking photographs in batches is so small, and the time occupied is so brief, when the necessary preparations have been made and the sitters are ready at hand, that a practice of methodically photographing schoolboys and members of other large institutions might easily be established. I, for one, should dearly prize the opportunity of visiting the places where I have been educated, and of turning over pages showing myself and my companions as we were in those days. But no such records exist; the institutions last and flourish, the individuals who pass through them are dispersed and leave few or no memorials behind. It seems a cruel waste of opportunity not to make and keep these brief personal records in a methodical manner. The fading of ordinary photographic prints is no real objection to keeping a register, because they can now be reproduced at small charge in permanent printers’ ink, by the autotype and other processes.
I have seen with admiration, and have had an opportunity of availing myself of, the newly-established library of well-ordered folios at the Admiralty, each containing a thousand pages, and each page containing a brief summary of references to the life of a particular seaman. There are already 80,000 pages, and owing to the excellent organisation of the office it is a matter of perfect ease to follow out any one of these references, and to learn every detail of the service of any seaman. A brief register of measurements and events in the histories of a large number of persons, previous to their entering any institution and during their residence in it, need not therefore be a difficult matter to those who may take it in hand seriously and methodically.
The recommendation I would venture to make to my readers is to obtain photographs and ordinary measurements periodically of themselves and their children, making it a family custom to do so, because, unless driven by some custom, the act will be postponed until the opportunity is lost. Let those periodical photographs be full and side views of the face on an adequate scale, adding any others that may be wished, but not omitting these. As the portraits accumulate have collections of them autotyped. Keep the prints methodically in a family register, writing by their side careful chronicles of illness and all such events as used to find a place on the fly-leaf of the Bible of former generations, and inserting other interesting personal facts and whatever anthropometric data can be collected.
Those who care to initiate and carry on a family chronicle illustrated by abundant photographic portraiture, will produce a work that they and their children and their descendants in more remote generations will assuredly be grateful for. The family tie has a real as well as a traditional significance. The world is beginning to awaken to the fact that the life of the individual is in some real sense a prolongation of those of his ancestry. His vigour, his character, and his diseases are principally derived from theirs; sometimes his faculties are blends of ancestral qualities; but more frequently they are mosaics, patches of resemblance to one or other of them showing now here and now there. The life-histories of our relatives are prophetic of our own futures; they are far more instructive to us than those of strangers, far more fitted to encourage and to forewarn us. If there be such a thing as a natural birthright, I can conceive of none superior to the right of the child to be informed, at first by proxy through his guardians, and afterwards personally, of the life-history, medical and other, of his ancestry. The child is thrust into existence without his having any voice at all in the matter, and the smallest amend that those who brought him here can make, is to furnish him with all the guidance they can, including the complete life-histories of his near progenitors.
The investigation of human eugenics–that is, of the conditions under which men of a high type are produced–is at present extremely hampered by the want of full family histories, both medical and general, extending over three or four generations. There is no such difficulty in investigating animal eugenics, because the generations of horses, cattle, dogs, etc., are brief, and the breeder of any such stock lives long enough to acquire a large amount of experience from his own personal observation. A man, however, can rarely be familiar with more than two or three generations of his contemporaries before age has begun to check his powers; his working experience must therefore be chiefly based upon records. Believing, as I do, that human eugenics will become recognised before long as a study of the highest practical importance, it seems to me that no time ought to be lost in encouraging and directing a habit of compiling personal and family histories. If the necessary materials be brought into existence, it will require no more than zeal and persuasiveness on the part of the future investigator to collect as large a store of them as he may require.
UNCONSCIOUSNESS OF PECULIARITIES.
The importance of submitting our faculties to measurement lies in the curious unconsciousness in which we are apt to live of our personal peculiarities, and which our intimate friends often fail to remark. I have spoken of the ignorance of elderly persons of their deafness to high notes, but even the existence of such a peculiarity as colour blindness was not suspected until the memoir of Dalton in 1794. That one person out of twenty-nine or thereabouts should be unable to distinguish a red from a green, without knowing that he had any deficiency of colour sense, and without betraying his deficiency to his friends, seems perfectly incredible to the other twenty-eight; yet as a matter of fact he rarely does either the one or the other. It is hard to convince the colour-blind of their own infirmity. I have seen curious instances of this: one was that of a person by no means unpractised in physical research, who had been himself tested in matching colours. He gave me his own version of the result, to the effect that though he might perhaps have fallen a little short of perfection as judged by over-refined tests, his colour sense was for all practical purposes quite good. On the other hand, the operator assured me that when he had toned the intensities of a pure red and a pure green in a certain proportion, the person ceased to be able to distinguish between them! Colour blindness is often very difficult to detect, because the test hues and tints may be discriminated by other means than by the normal colour sense. Ordinary pigments are never pure, and the test colours may be distinguished by those of their adventitious hues to which the partly colour-blind man may be sensitive. We do not suspect ourselves to be yellow-blind by candle light, because we enjoy pictures in the evening nearly or perhaps quite as much as in the day time; yet we may observe that a yellow primrose laid on the white table-cloth wholly loses its colour by candle light, and becomes as white as a snowdrop.
In the inquiries I made on the hereditary transmission of capacity, I was often amused by the naive remark of men who had easily distanced their competitors, that they ascribed their success to their own exertions. They little recognised how much they owed to their natural gifts of exceptional capacity and energy on the one hand, and of exceptional love for their special work on the other.
In future chapters I shall give accounts of persons who have unusual mental characteristics as regards imagery, visualised numerals, colours connected with sounds and special associations of ideas, being unconscious of their peculiarities; but I cannot anticipate these subjects here, as they all require explanation. It will be seen in the end how greatly metaphysicians and psychologists may err, who assume their own mental operations, instincts, and axioms to be identical with those of the rest of mankind, instead of being special to themselves. The differences between men are profound, and we can only be saved from living in blind unconsciousness of our own mental peculiarities by the habit of informing ourselves as well as we can of those of others. Examples of the success with which this can be done will be found farther on in the book.
I may take this opportunity of remarking on the well-known hereditary character of colour blindness in connection with the fact, that it is nearly twice as prevalent among the Quakers as among the rest of the community, the proportions being as 5.9 to 3.5 per cent.  We might have expected an even larger ratio. Nearly every Quaker is descended on both sides solely from members of a group of men and women who segregated themselves from the rest of the world five or six generations ago; one of their strongest opinions being that the fine arts were worldly snares, and their most conspicuous practice being to dress in drabs. A born artist could never have consented to separate himself from his fellows on such grounds; he would have felt the profession of those opinions  and their accompanying practices to be a treason to his aesthetic nature. Consequently few of the original stock of Quakers are likely to have had the temperament that is associated with a love for colour, and it is in consequence most reasonable to believe that a larger proportion of colour-blind men would have been found among them than among the rest of the population.
[Footnote 5: _Trans. Ophthalmological Soc_., 1881, p. 198.]
Again, Quakerism is a decreasing sect, weakened by yearly desertions and losses, especially as the act of marriage with a person who is not a member of the Society is necessarily followed by exclusion from it. It is most probable that a large proportion of the deserters would be those who, through reversion to some bygone ancestor, had sufficient artistic taste to make a continuance of Quaker practices too irksome to be endured. Hence the existing members of the Society of Friends are a race who probably contained in the first instance an unduly large proportion of colour-blind men, and from whose descendants many of those who were not born colour blind have year by year been drafted away. Both causes must have combined with the already well-known tendency of colour blindness to hereditary transmission, to cause it to become a characteristic of their race. Dalton, who first discovered its existence, as a personal peculiarity of his own, was a Quaker to his death; Young, the discoverer of the undulatory theory of light, and who wrote specially on colours, was a Quaker by birth, but he married outside the body and so ceased to belong to it.
The object of statistical science is to discover methods of condensing information concerning large groups of allied facts into brief and compendious expressions suitable for discussion. The possibility of doing this is based on the constancy and continuity with which objects of the same species are found to vary. That is to say, we always find, after sorting any large number of such objects in the order (let us suppose) of their lengths, beginning with the shortest and ending with the tallest, and setting them side by side like a long row of park palings between the same limits, their upper outline will be identical. Moreover, it will run smoothly and not in irregular steps. The theoretical interpretation of the smoothness of outline is that the individual differences in the objects are caused by different combinations of a large number of minute influences; and as the difference between any two adjacent objects in a long row must depend on the absence in one of them of some single influence, or of only a few such, that were present in the other, the amount of difference will be insensible. Whenever we find on trial that the outline of the row is not a flowing curve, the presumption is that the objects are not all of the same species, but that part are affected by some large influence from which the others are free; consequently there is a confusion of curves. This presumption is never found to be belied.
It is unfortunate for the peace of mind of the statistician that the influences by which the magnitudes, etc., of the objects are determined can seldom if ever be roundly classed into large and small, without intermediates. He is tantalised by the hope of getting hold of sub-groups of sufficient size that shall contain no individuals except those belonging strictly to the same species, and he is almost constantly baffled. In the end he is obliged to exercise his judgment as to the limit at which he should cease to subdivide. If he subdivides very frequently, the groups become too small to have statistical value; if less frequently, the groups will be less truly specific.
A species may be defined as a group of objects whose individual differences are wholly due to different combinations of the same set of minute causes, no one of which is so powerful as to be able by itself to make any sensible difference in the result. A well-known mathematical consequence flows from this, which is also universally observed as a fact, namely, that in all species the number of individuals who differ from the average value, up to any given amount, is much greater than the number who differ more than that amount, and up to the double of it. In short, if an assorted series be represented by upright lines arranged side by side along a horizontal base at equal distances apart, and of lengths proportionate to the magnitude of the quality in the corresponding objects, then their shape will always resemble that shown in Fig. 1.
The form of the bounding curve resembles that which is called in architectural language an ogive, from “augive,” an old French word for a cup, the figure being not unlike the upper half of a cup lying sideways with its axis horizontal. In consequence of the multitude of mediocre values, we always find that on either side of the middlemost ordinate _Cc_, which is the median value and may be accepted as the average, there is a much less rapid change of height than elsewhere. If the figure were pulled out sideways to make it accord with such physical conceptions as that of a row of men standing side by side, the middle part of the curve would be apparently horizontal.
[Illustration: Fig. 1.]
[Illustration: Fig. 2.]
The mathematical conception of the curve is best expressed in Fig. 2, where PQ represents any given deviation from the average value, and the ratio of PO to AB represents the relative probability of its occurrence. The equation to the curve and a discussion of its properties will be found in the _Proceedings of the Royal Society_, No. 198, 1879, by Dr. M’Alister. The title of the paper is the “Law of the Geometric Mean,” and it follows one by myself on “The Geometric Mean in Vital and Social Statistics.”
We can lay down the ogive of any quality, physical or mental, whenever we are capable of judging which of any two members of the group we are engaged upon has the larger amount of that quality. I have called this the method of statistics by intercomparison. There is no bodily or mental attribute in any race of individuals that can be so dealt with, whether our judgment in comparing them be guided by common-sense observation or by actual measurement, which cannot be gripped and consolidated into an ogive with a smooth outline, and thenceforward be treated in discussion as a single object.
It is easy to describe any given ogive which has been based upon measurements, so that it may be drawn from the description with approximate truth. Divide AB into a convenient number of fractional parts, and record the height of the ordinates at those parts. In reproducing the ogive from these data, draw a base line of any convenient length, divide it in the same number of fractional parts, erect ordinates of the stated lengths at those parts, connect their tops with a flowing line, and the thing is done. The most convenient fractional parts are the middle (giving the median), the outside quarters (giving the upper and lower quartiles), and similarly the upper and lower octiles or deciles. This is sufficient for most purposes. It leaves only the outer eighths or tenths of the cases undescribed and undetermined, except so far as may be guessed by, the run of the intermediate portion of the curve, and it defines all of the intermediate portion with as close an, approximation as is needed for ordinary or statistical purposes.
Thus the heights of all but the outer tenths of the whole body of adult males of the English professional classes may be derived from the five following ordinates, measured in inches, of which the outer pair are deciles:–
67.2; 67.5; 68.8; 70.3; 71.4.
Many other instances will be found in the Report of the Anthropometric Committee of the British Association in 1881, pp. 245-257.
When we desire to compare any two large statistical groups, we may compare median with median, quartiles with quartiles, and octiles with octiles; or we may proceed on the method to be described in the next paragraph but one.
We are often called upon to define the position of an individual in his own series, in which case it is most conformable to usage to give his centesimal grade–that is, his place on the base line AB–supposing it to be graduated from 0 deg. to 100 deg. In reckoning this, a confusion ought to be avoided between “graduation” and “rank,” though it leads to no sensible error in practice. The first of the “park palings” does not stand at A, which is 0 deg., nor does the hundredth stand at B, which is 100 deg., for that would make 101 of them: but they stand at 0 deg.5 and 99 deg.5 respectively. Similarly, all intermediate _ranks_ stand half a degree short of the _graduation_ bearing the same number. When the class is large, the value of half a place becomes extremely small, and the rank and graduation may be treated as identical.
Examples of method of calculating a centesimal position:–
1. A child A is classed after examination as No. 5 in a class of 27 children; what is his centesimal graduation?
_Answer_.–If AB be divided into 27 graduations, his rank of No. 5