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  • 1883
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the appearance of lying on the screen, the frame being so adjusted that the distance from the thin piece of glass to the transparency and to the glass-screen _g_ is the same. I thus obtain beautiful fiducial lines, which I can vary from extreme faintness to extreme brilliancy, by turning the gas lower or higher, according to the brightness of the image of the portrait, which itself depends on the density of the transparency that I am engaged upon. This arrangement seems as good as can be. It affords a gauge of the density of the negative, and enables me to regulate the burners behind it, until the image of the portrait on _g_ is adjusted to a standard degree of brightness.

For convenience in enlarging or reducing, I take care that the intersection of the vertical fiducial line with that which passes through the pupils of the eyes shall correspond to the optical axis of the camera. Then, as I enlarge or reduce, that point in the image remains fixed. The uppermost horizontal fiducial line continues to intersect the pupils, and the vertical one continues to divide the face symmetrically. The mouth has alone to be watched. When the mouth is adjusted to the lower fiducial line, the scale is exact. It is a great help having to attend to no more than one varying element. The only inconvenience is that the image does not lie in the best position on the plate when the point between the eyes occupies its centre. This is easily remedied by using a larger back with a suitable inner frame. I have a more elaborate contrivance in my apparatus to produce the same result, which I need not stop to explain.

For success and speed in making composites, the apparatus should be solidly made, chiefly of metal, and all the adjustments ought to work smoothly and accurately. Good composites cannot be made without very careful adjustment in scale and position. An off-hand way of working produces nothing but failures.

I will first exhibit a very simple but instructive composite effect. I drew on a square card a circle of about 2-1/2 inches in diameter, and two cross lines through its centre, cutting one another at right angles. Round each of the four points, 90 deg. apart, where the cross cuts the circle, I drew small circles of the size of wafers and gummed upon each a disc of different tint. Finally I made a single black dot half-way between two of the arms of the cross. I then made a composite of the four positions of the card, as it was placed successively with each of its sides downwards. The result is a photograph having a sharply-defined cross surrounded by four discs of precisely uniform tint, and between each pair of arms of the cross there is a very faint dot. This photograph shows many things. The fact of its being a composite is shown by the four faint dots. The equality of the successive periods of exposure is shown by the equal tint of the four dots. The accuracy of adjustment is shown by the sharpness of the cross being as great in the composite as in the original card. We see the smallness of the effect produced by any trait, such as the dot, when it appears in the same place in only one of the components: if this effect be so small in a series of only four components, it would certainly be imperceptible in a much larger series. Thirdly, the uniformity of resulting tint in the composite wafer is quite irrespective of the order of exposure. Let us call the four component wafers A, B, C, D, respectively, and the four composite wafers 1, 2, 3, 4; then we see, by the diagram, that the order of exposure has differed in each case, yet the result is identical. Therefore the order of exposure has no effect on the result.

|———-+————————————| |Composite.|Successive places of the Components.| | 1 2 | A B | D A | C D | B C |
| 4 3 | D C | C B | B A | A D | |===============================================|

In 1 it has been A, D, C, B,
” 2 ” B, A, D, C,
” 3 ” C, B, A, D,
” 4 ” D, C, B, A,

I will next show a series consisting of two portraits considerably unlike to one another, and yet not so very discordant as to refuse to conform, and of two intermediate composites. In making one of the composites I gave two-thirds of the total time of exposure to the first portrait, and one-third to the second portrait. In making the other composite, I did the converse. It will be seen how good is the result in both cases, and how the likeness of the longest exposed portrait always predominates.

The next is a series of four composites. The first consists of 57 hospital patients suffering under one or other of the many forms of consumption. I may say that, with the aid of Dr. Mahomed, I am endeavouring to utilise this process to elicit the physiognomy of disease. The composite I now show is what I call a hotch-pot composite; its use is to form a standard whence deviations towards any particular sub-type may be conveniently gauged. It will be observed that the face is strongly marked, and that it is quite idealised. I claim for composite portraiture, that it affords a method of obtaining _pictorial averages_, which effects simultaneously for every point in a picture what a method of numerical averages would do for each point in the picture separately. It gives, in short, the average tint of every unit of area in the picture, measured from the fiducial lines as co-ordinates. Now every statistician knows, by experience, that numerical averages usually begin to agree pretty fairly when we deal with even twenty or thirty cases. Therefore we should expect to find that any groups of twenty or thirty men of the same class would yield composites bearing a considerable likeness to one another. In proof that this is the case, I exhibit three other composites: the one is made from the first 28 portraits of the 57, the second from the last 27, and the third is made from 36 portraits taken indiscriminately out of the 57. It will be observed that all the four composites are closely alike.

I will now show a few typical portraits I selected out of 82 male portraits of a different series of consumptive male patients; they were those that had more or less of a particular wan look, that I wished to elicit. The selected cases were about 18 in number, and from these I took 12, rejecting about six as having some marked peculiarity that did not conform well with the remaining 12. The result is a very striking face, thoroughly ideal and artistic, and singularly beautiful. It is, indeed, most notable how beautiful all composites are. Individual peculiarities are all irregularities, and the composite is always regular.

I show a composite of 15 female faces, also of consumptive patients, that gives somewhat the same aspect of the disease; also two others of only 6 in each, that have in consequence less of an ideal look, but which are still typical. I have here several other typical faces in my collection of composites; they are all serviceable as illustrations of this memoir, but, medically speaking, they are only provisional results.

I am indebted to Lieutenant Leonard Darwin, R.E., for an interesting series of negatives of officers and privates of the Royal Engineers. Here is a composite of 12 officers; here is one of 30 privates. I then thought it better to select from the latter the men that came from the southern counties, and to again make a further selection of 11 from these, on the principle already explained. Here is the result. It is very interesting to note the stamp of culture and refinement on the composite officer, and the honest and vigorous but more homely features of the privates. The combination of these two, officers and privates together, gives a very effective physiognomy.

Let it be borne in mind that existing cartes-de-visite are almost certain to be useless. Among dozens of them it is hard to find three that fulfil the conditions of similarity of aspect and of shade. The negatives have to be made on purpose. I use a repeating back and a quarter plate, and get two good-sized heads on each plate, and of a scale that never gives less than four-tenths of an inch between the pupils of the eyes and the mouth. It is only the head that can be used, as more distant parts, even the ears, become blurred hopelessly.

It will be asked, of what use can all this be to ordinary photographers, even granting that it may be of scientific value in ethnological research, in inquiries into the physiognomy of disease, and for other special purposes? I think it can be turned to most interesting account in the production of family likenesses. The most unartistic productions of amateur photography do quite as well for making composites as those of the best professional workers, because their blemishes vanish in the blended result. All that amateurs have to do is to take negatives of the various members of their families in precisely the same aspect (I recommend either perfect full-face or perfect profile), and under precisely the same conditions of light and shade, and to send them to a firm provided with proper instrumental appliances to make composites from them. The result is sure to be artistic in expression and flatteringly handsome, and would be very interesting to the members of the family. Young and old, and persons of both sexes can be combined into one ideal face. I can well imagine a fashion setting in to have these pictures.

Professional skill might be exercised very effectively in retouching composites. It would be easy to obliterate the ghosts of stray features that are always present when the composite is made from only a few portraits, and it would not be difficult to tone down any irregularity in the features themselves, due to some obtrusive peculiarity in one of the components. A higher order of artistic skill might be well bestowed upon the composites that have been made out of a large number of components. Here the irregularities disappear, the features are perfectly regular and idealised, but the result is dim. It is like a pencil drawing, where many attempts have been made to obtain the desired effect; such a drawing is smudged and ineffective; but the artist, under its guidance, draws his final work with clear bold touches, and then he rubs out the smudge. On precisely the same principle the faint but beautifully idealised features of these composites are, I believe, capable of forming the basis of a very high order of artistic work.


[_Read before the Statistical Society in_ 1873.]

It is well known that the population of towns decays, and has to be recruited by immigrants from the country, but I am not aware that any statistical investigation has yet been attempted of the rate of its decay. The more energetic members of our race, whose breed is the most valuable to our nation, are attracted from the country to our towns. If residence in towns seriously interferes with the maintenance of their stock, we should expect the breed of Englishmen to steadily deteriorate, so far as that particular influence is concerned.

I am well aware that the only perfectly trustworthy way of conducting the inquiry is by statistics derived from numerous life-histories, but I find it very difficult to procure these data. I therefore have had recourse to an indirect method, based on a selection from the returns made at the census of 1871, which appears calculated to give a fair approximation to the truth. My object is to find the number of adult male representatives in this generation, of 1000 adult males in the previous one, of rural and urban populations respectively. The principle on which I have proceeded is this:–

I find (A) the number of children of equal numbers of urban and of rural mothers. The census schedules contain returns of the names and ages of the members of each “family,” by which word we are to understand those members who are alive and resident in the same house with their parents. When the mothers are young, the children are necessarily very young, and nearly always (in at least those classes who are unable to send their children to boarding schools) live at home. If, therefore, we limit our inquiries to the census “families” of young mothers, the results may be accepted as practically identical with those we should have obtained if we had direct means of ascertaining the number of their living children. The limits of age of the mothers which I adopted in my selection were, 24 and 40 years. Had I to begin the work afresh, I should prefer the period from 20 to 35, but I have reason to feel pretty well contented with my present data. I correct the results thus far obtained on the following grounds:–(B) the relative mortality of the two classes between childhood and maturity; (C) the relative mortality of the rural and urban mothers during childbearing ages; (D) their relative celibacy; and (E) the span of a rural and urban generation. It will be shown that B is important, and C noteworthy, but that D and E may be disregarded.

In deciding on the districts to be investigated, it was important to choose well-marked specimens of urban and rural populations. In the former, a town was wanted where there were various industries, and where the population was not increasing. A town where only one industry was pursued would not be a fair sample, because the particular industry might be suspected of having a special influence, and a town that was increasing would have attracted numerous immigrants from the country, who are undistinguishable as such in the census returns. Guided by these considerations, I selected Coventry, where silk weaving, watch-making, and other industries are carried on, and whose population had scarcely varied during the decade preceding the census of 1871.[25] It is an open town, in which the crowded alleys of larger places are not frequent. Its urban peculiarities are therefore minimised, and its statistical returns would give a picture somewhat too favourable of the average condition of life in towns. For specimens of rural districts, I chose small agricultural parishes in Warwickshire.

[Footnote 25: It has greatly changed since this was written.]

By the courteous permission of Dr. Farr, I was enabled to procure extracts from the census returns concerning 1000 “families” of factory hands at Coventry, in which the age of the mother was neither less than 24 nor more than 40 years, and concerning another 1000 families of agricultural labourers in rural parishes of Warwickshire, under the same limitations as to the age of the mother. When these returns were classified (see Table I., p. 246), I found the figures to run in such regular sequence as to make it certain that the cases were sufficiently numerous to give trustworthy results. It appeared that:

(A) The 1000 families of factory hands comprised 2681 children, and the 1000 of agricultural labourers comprised 2911; hence, the children in the urban “families,” the mothers being between the ages of 24 and 40, are on the whole about 8 per cent, less numerous than the rural. I see no reason why these numbers should not be accepted as relatively correct for families, in the ordinary sense of that word, and for mothers of all ages. An inspection of the table does indeed show that if the selection had begun at an earlier age than 24, there would have been an increased proportion of sterile and of small families among the factory hands, but not sufficient to introduce any substantial modification of the above results. It is, however, important to recollect that the small error, whatever its amount may be, is a concession in favour of the towns.

(B) I next make an allowance for the mortality between childhood and maturity, which will diminish the above figures in different proportions, because the conditions of town life are more fatal to children than those of the country. No life tables exist for Coventry and Warwickshire; I am therefore obliged to use statistics for similarly conditioned localities, to determine the amount of the allowance that should be made. The life tables of Manchester [26] will afford the data for towns, and those of the “Healthy Districts” [27] will suffice for the country. By applying these, we could calculate the number of the children of ages specified in the census returns who would attain maturity. I regret extremely that when I had the copies taken, I did not give instructions to have the ages of all the children inserted; but I did not, and it is too late now to remedy the omission. I am therefore obliged to make a very rough, but not unfair, estimate. The average age of the children was about 3 years, and 25 years may be taken as representing the age of maturity. Now it will be found that 74 per cent. of children in Manchester, of the age of 3, reach the age of 25, while 86 per cent. of children do so in the “Healthy Districts.” Therefore, if my rough method be accepted as approximately fair, the number of adults who will be derived from the children of the 1000 factory families should be reckoned at (2681 x 74/100) = 1986, and those from the 1000 agricultural at (2911 x 86/100) = 2503.

[Footnote 26: “Seventh Annual Report of Registrar-General.”]

[Footnote 27: Healthy Districts Life Table, by Dr. Farr. _Phil Trans. Royal Society_, 1859.]

(C) The comparison we seek is between the total families produced by an equal number of urban and rural women who had survived the age of 24. Many of these women will not marry at all; I postpone that consideration to the next paragraph. Many of the rest will die before they reach the age of 40, and more of them will die in the town than in the country. It appears from data furnished by the above-mentioned tables, that if 100 women of the age of 24 had annually been added to a population, the number of those so added, living between the ages of 24 and 40 (an interval of seventeen years) would be 1539 under the conditions of life in Manchester, and 1585 under those of the healthy districts. Therefore the small factors to be applied respectively to the two cases, on account of this correction, are 1539/(17 x 100) and 1585/(17 x 100).

(D) I have no trustworthy data for the relative prevalence of celibacy in town and country. All that I have learned from the census returns is, that when searching them for the 1000 families, 131 bachelors were noted between the ages of 24 and 40, among the factory hands, and 144 among the agricultural labourers. If these figures be accepted as correct guides to the amount of celibacy among the women, it would follow that I must be considered to have discussed the cases of 1131 factory, and 1144 agricultural women, when dealing with those of 1000 mothers in either class. Consequently that the respective corrections to be applied, are given by the factors 1000/1131 and 1000/1141 or 88.4/1000 and 87.6/ 1000. This difference of less than 1 per cent, is hardly worth applying, moreover I do not like to apply it, because it seems to me erroneous and to act in the wrong direction, inasmuch as unmarried women can obtain employment more readily in the town than in the country, and celibacy is therefore more likely to be common in the former than in the latter.

(E) The possible difference in the length of an urban and rural generation must not be forgotten. We, however, have reason to believe that the correction on this ground will be insignificant, because the length of a generation is found to be constant under very different circumstances of race, and therefore we should expect it to be equally constant in the same race under different conditions; such as it is, it would probably tell against the towns.

Let us now sum up the results. The corrections are not to be applied for (D) and (E), so we have only to regard (A) x (B) x (C), that this–

2681 x 74/100 x 1539/1700 1796 77
————————- = —- = — 2911 x 86/100 x 1585/1700 2334 100

In other words, the rate of supply in towns to the next adult generation is only 77 per cent., or, say, three-quarters of that in the country. This decay, if it continued constant, would lead to the result that the representatives of the townsmen would be less than half as numerous as those of the country folk after one century, and only about one fifth as numerous after two centuries, the proportions being 45/100 and 21/100 respectively.

[Transcriber’s Note: In the original manuscript, Table I occupied two facing pages. This is the left-hand (sinister) page; the right-hand (dexter) page is immediately below.]

TABLE I. — _Census Returns of 1000 Families of Factory Hands in Coventry, and 1000 Families of Agricultural Labourers in Warwickshire, grouped according to the Age of the Mother and the Number of Children in the Family._

————————————————— |NUMBER OF CHILDREN IN FAMILY. | |———|———|———|———-|——–| | 0. | 1. | 2. | 3. | 4. | |———+———+———+———-+——–| | F | A | F | A | F | A | F | A | F | A | | a | g | a | g | a | g | a | g | a | g | | c | r | c | r | c | r | c | r | c | r | | t | i | t | i | t | i | t | i | t | i | | o | c | o | c | o | c | o | c | o | c | | r | u | r | u | r | u | r | u | r | u | Age of Mother | y | l | y | l | y | l | y | l | y | l | | . | t | . | t | . | t | . | t | . | t | ————————————————— 24 to 25 | 28 17 40 31 | 24 32 12 10 2 | | +——————-+ | 26 ” 27 | 19 18 36 24 36 28 23 26 | 8 8 | | | |
28 ” 29 | 18 17 32 16 20[A] 33 36 23 | 14 23 | | | |
30 ” 31 | 13 4 23 18 24 21 28[A] 31 | 18 22 | | | |
32 ” 33 | 18 11 16 14 19 13 22[A] 27 | 23 26 | |———+ | | 34 ” 35 | 14 15 | 11 6 17 16 28 18 | 31 34 | | +——————-+ | | 36 ” 37 | 12 17 4 11 10 13 | 22 14 | 16 20 | | +———+ | 38 ” 39 | 8 6 9 15 14 17 16 21 22 23 | | |
40 | 8 7 3 10 8 9 13 14 8 10 | ===============|=================================================| Total within | | outline | 96 67 258 109 116 111 171 149 | Total between | | outlines | 42 45 16 36 56 71 29 35 142 166 | Total beyond | | outline | |
===============|=================================================| Total |138 112 174 145 172 182 200 184 142 166 | ===============|=================================================|

[Footnote A: These three cases are anomalous, the Factory being less than the Agricultural. In the instance of 20-33, the anomaly is double, because the sequence of the figures shows that neither of these can be correct; certainly not the first of them.]

_Note_.–It will be observed to the left of the outline, that is, in the upper and left hand of the table, where the mothers are young and the children few, the factory families predominate, while the agricultural are the most numerous between the outlines, that is, especially in the middle of the table, where the mothers are less young, and the family is from four to five in number. The two are equally numerous to the right of the outlines, that is, to the right of the table, where the families are large.

[Transcriber’s Note: In the original manuscript, Table I occupied two facing pages. This is the right-hand (dexter) page; the left-hand (snister) page is immediately above.]

TABLE I. — _Census Returns of 1000 Families of Factory Hands in Coventry, and 1000 Families of Agricultural Labourers in Warwickshire, grouped according to the Age of the Mother and the Number of Children in the Family._

| NUMBER OF CHILDREN IN FAMILY. | |————————————————-| | 5. | 6. | 7. | 8. | 9. |
|———+———+———+———+———| | F | A | F | A | F | A | F | A | F | A | | a | g | a | g | a | g | a | g | a | g | | c | r | c | r | c | r | c | r | c | r | | t | i | t | i | t | i | t | i | t | i | | o | c | o | c | o | c | o | c | o | c | | r | u | r | u | r | u | r | u | r | u | | y | l | y | l | y | l | y | l | y | l |Age of Mother | . | t | . | t | . | t | . | t | . | t | |———+———+———+———+———|———— | 1 1 | | 24 to 25
| | |
| | | 26 ” 27 | | |
| 6 6 | 4 1 2 | 28 ” 29 | | |
| 12 15 | 2 5 2 1 | 30 ” 31 | | |
| 21 25 | 9 5 1 2 | 32 ” 33 | | |
| 14 18 | 12 9 5 3 1 | 34 ” 35 | | |
| 15 25 | 12 10 4 5 5 2 | 36 ” 37 | | |
| 14 22 | 10 15 6 7 2 1 | 38 ” 39 | | |
| 7 11 | 3 9 7 7 2 1 | 40 |=================================================|——————– | |Total within outline. | 90 123 |Total between outline | 52 54 24 25 7 9 1 |Total beyond outline. |=================================================|===================== | 90 123 52 54 24 25 7 9 1 |Total. |=======================================================================


|———————————————————————-| | | Number of Families | Number of Children | | |——–+————–+————————| | | Factory| Agricultural | Factory | Agricultural | | Within outline | 541 | 436 | 903 | 778 | | Between outlines | 375 | 476 | 1233 | 1562 | | Beyond outlines | 84 | 88 | 545 | 571 | |=============================================+========================| | Total | 1000 | 1000 | 2681 | 2911 | |======================================================================|


[_Read at the Anthropological Institute_, Nov., 1882.]

I submit a simple apparatus that I have designed to measure the delicacy of the sensitivity of different persons, as shown by their skill in discriminating weights, identical in size, form, and colour, but different in specific gravity. Its interest lies in the accordance of the successive test values with the successive graduations of a true scale of sensitivity, in the ease with which the tests are applied, and the fact that the same principle can be made use of in testing the delicacy of smell and taste.

I use test-weights that mount in a series of “just perceptible differences” to an imaginary person of extreme delicacy of perception, their values being calculated according to Weber’s law. The lowest weight is heavy enough to give a decided sense of weight to the hand when handling it, and the heaviest weight can be handled without any sense of fatigue. They therefore conform with close approximation to a geometric series; thus–
_WR0, WR1, WR2, WR3_, etc.,
and they bear as register-marks the values of the successive indices, 0, 1, 2, 3, etc. It follows that if a person can just distinguish between any particular pair of weights, he can also just distinguish between any other pair of weights whose register-marks differ by the same amount. Example: suppose A can just distinguish between the weights bearing the register-marks 2 and 4, then it follows from the construction of the apparatus that he can just distinguish between those bearing the register-marks 1 and 3, or 3 and 5, or 4 and 6, etc.; the difference being 2 in each case.

There can be but one interpretation of the phrase that the dulness of muscular sense in any person, B, is twice as great as in that of another person, A. It is that B is only capable of perceiving one grade of difference where A can perceive two. We may, of course, state the same fact inversely, and say that the delicacy of muscular sense is in that case twice as great in A as in B. Similarly in all other cases of the kind. Conversely, if having known nothing previously about either A or B, we discover on trial that A can just distinguish between two weights such as those bearing the register-marks 5 and 7, and that B can just distinguish between another pair, say, bearing the register-marks 2 and 6; then since the difference between the marks in the latter case is twice as great as in the former, we know that the dulness of the muscular sense of B is exactly twice that of A. Their relative dulness, or if we prefer to speak in inverse terms, and say their relative sensitivity, is determined quite independently of the particular pair of weights used in testing them.

It will be noted that the conversion of results obtained by the use of one series of test-weights into what would have been given by another series, is a piece of simple arithmetic, the fact ultimately obtained by any apparatus of this kind being the “just distinguishable” fraction of real weight. In my own apparatus the unit of weight is 2 per cent.; that is, the register-mark 1 means 2 per cent.; but I introduce weights in the earlier part of the scale that deal with half units; that is, with differences of 1 per cent. In another apparatus the unit of weight might be 3 per cent., then three grades of mine would be equal to two of the other, and mine would be converted to that scale by multiplying them by 2/3. Thus the results obtained by different apparatus are strictly comparable.

A sufficient number of test-weights must be used, or trials made, to eliminate the influence of chance. It might perhaps be thought that by using a series of only five weights, and requiring them to be sorted into their proper order by the sense of touch alone, the chance of accidental success would be too small to be worth consideration. It might be said that there are 5 x 4 x 3 x 2, or 120 different ways in which five weights can be arranged, and as only one is right, it must be 120 to 1 against a lucky hit. But this is many fold too high an estimate, because the 119 possible mistakes are by no means equally probable. When a person is tested, an approximate value for his grade of sensitivity is rapidly found, and the inquiry becomes narrowed to finding out whether he can surely pass a particular mistake. He is little likely to make a mistake of double the amount in question, and it is almost certain that he will not make a mistake of treble the amount. In other words, he would never be likely to put one of the test-weights more than one step out of its proper place. If he had three weights to arrange in their consecutive order, 1, 2, 3, there are 3×2 = 6 ways of arranging them; of these, he would be liable to the errors of 1, 3, 2, and of 2, 1, 3, but he would hardly be liable to such gross errors as 2, 3, 1, or 3, 2, 1, or 3, 1, 2. Therefore of the six permutations in which three weights may be arranged three have to be dismissed from consideration, leaving three cases only to be dealt with, of which two are wrong and one is right. For the same reason there are only four reasonable chances of error in arranging four weights, and only six in arranging five weights, instead of the 119 that were originally supposed. These are–

12354 13245 13254
21345 21354 21435

But exception might be taken to two even of these, namely, those that appear in the third column, where 5 is found in juxtaposition with 2 in the first case, and 4 with 1 in the second. So great a difference between two adjacent weights would be almost sure to attract the notice of the person who was being tested, and make him dissatisfied with the arrangement. Considering all this, together with the convenience of carriage and manipulation, I prefer to use trays, each containing only three weights, the trials being made three or four times in succession. In each trial there are three possibilities and only one success, therefore in three trials the probabilities against uniform success are as 27 to 1, and in four trials at 81 to 1.

_Values of the Weights_.–After preparatory trials, I adopted 1000 grains as the value of _W_ and 1020 as that of _R_, but I am now inclined to think that 1010 would have been better. I made the weights by filling blank cartridges with shot, wool, and wads, so as to distribute the weight equally, and I closed the cartridges with a wad, turning the edges over it with the instrument well known to sportsmen. I wrote the corresponding value of the index of _R_ on the wad by which each of them was closed, to serve as a register number. Thus the cartridge whose weight was _WR4_ was marked 4′. The values were so selected that there should be as few varieties as possible. There are thirty weights in all, but only ten varieties, whose Register Numbers are respectively 0, 1, 2, 3, 3-1/2, 4-1/2, 5, 6, 7, 9, 12. The reason of this limitation of varieties was to enable the weights to be interchanged whenever there became reason to suspect that the eye had begun to recognise the appearance of any one of them, and that the judgment might be influenced by that recognition, and cease to be wholly guided by the sense of weight.

We are so accustomed to deal with concurrent impressions that it is exceedingly difficult, even with the best intention of good faith, to ignore the influence of any corroborative impression that may be present. It is therefore right to take precautions against this possible cause of inaccuracy. The most perfect way would be to drop the weights, each in a little bag or sheath of light material, so that the operatee could not see the weights, while the ratio between the weights would not be sensibly changed by the additional weight of the bags. I keep little bags for this purpose, inside the box that holds the weights.

_Arrangement of the Weights_.–The weights are placed in sets of threes, each set in a separate shallow tray, and the trays lie in two rows in a box. Each tray bears the register-marks of each of the weights it contains. It is also marked boldly with a Roman numeral showing the difference between the register-marks of the adjacent weights. This difference indicates the grade of sensitivity that the weights in the tray are designed to test. Thus the tray containing the weights _WR0_, _WR3_, _WR6_ is marked as in Fig. 1, and that which contains _WR2_, _WR7_, _WR12_ is marked as in Fig. 2.

[Illustration: Fig. 1.]

[Illustration: Fig. 2.]

The following is the arrangement of the trays in the box. The triplets they contain suffice for ordinary purposes.

|=========================================| | Just | | |
| perceptible | Grade of | Sequences | | Ratio. | Sensitivity | of Weights |
|————-+————-+————-| | 1.020 | I. | 1, 2, 3 |
| 1.030 | I.1/2 | 2, 3-1/2, 5 | | 1.040 | II. | 3, 5, 7 |
| 1.050 | II.1/2 | 2, 4-1/2, 7 | | 1.061 | III. | 0, 3, 6 |
| 1.071 | III.1/2 | 0, 3-1/2, 7 | | 1.082 | IV. | 1, 5, 9 |
| 1.082 | IV.1/2 | 0, 4-1/2, 9 | | 1.104 | V. | 2, 5, 7 |
| 1.127 | VI. | 0, 6, 12 |

But it will be observed that sequences of 1/2 can also be obtained, and again, that it is easy to select doublets of weights for coarser tests, up to a maximum difference of XII., which may be useful in cases of morbidly diminished sensitivity.

_Manipulation_.–A tray is taken out, the three weights that it contains is shuffled by the operator who then passes them on to the experimenter. The latter sits at ease with his hand in an unconstrained position, and lifts the weights in turn between his finger and thumb, the finger pressing against the top, the thumb against the bottom of the cartridge. Guided by the touch alone, he arranges them in the tray in what he conceives to be their proper sequence; he then returns the tray to the operator, who notes the result, the operator then reshuffles the weights and repeats the trial. It is necessary to begin with coarse preparatory tests, to accustom the operatee to the character of the work. After a minute or two the operator may begin to record results, and the testing may go for several minutes, until the hand begins to tire, the judgment to be confused, and blunders to arise. Practice does not seem to increase the delicacy of perception after the first few trials, so much as might be expected.


The base of the inner tube of the whistle is the foremost end of a plug, that admits of being advanced or withdrawn by screwing it out or in; thus the depth of the inner tube of the whistle can be varied at pleasure. The more nearly the plug is screwed home, the less is the depth of the whistle and the more shrill does its note become, until a point is reached at which, although the air that proceeds from it vibrates as violently as before, as shown by its effect on a sensitive flame, the note ceases to be audible.

The number of vibrations per second in the note of a whistle or other “closed pipe” depends on its depth. The theory of acoustics shows that the length of each complete vibration is four times that of the depth of the closed pipe, and since experience proves that all sound, whatever may be its pitch, is propagated at the same rate, which under ordinary conditions of temperature and barometric pressure may be taken at 1120 feet, or 13,440 inches per second,–it follows that the number of vibrations in the note of a whistle may be found by dividing 13,440 by four times the depth, measured in inches, of the inner tube of the whistle. This rule, however, supposes the vibrations of the air in the tube to be strictly longitudinal, and ceases to apply when the depth of the tube is less than about one and a half times its diameter. When the tube is reduced to a shallow pan, a note may still be produced by it, but that note has reference rather to the diameter of the whistle than to its depth, being sometimes apparently unaltered by a further decrease of depth. The necessity of preserving a fair proportion between the diameter and the depth of a whistle is the reason why these instruments, having necessarily little depth, require to be made with very small bores.

The depth of the inner tube of the whistle at any moment is shown by the graduations on the outside of the instrument. The lower portion of the instrument as formerly made for me by the late Mr. Tisley, optician, Brompton Road,[28] is a cap that surrounds the body of the whistle, and is itself fixed to the screw that forms the plug. One complete turn of the cap increases or diminishes the depth of the whistle, by an amount equal to the interval between two adjacent threads of the screw. For mechanical convenience, a screw is used whose pitch is 25 to the inch; therefore one turn of the cap moves the plug one twenty-fifth of an inch, or ten two-hundred-and-fiftieths. The edge of the cap is divided into ten parts, each of which corresponds to the tenth of a complete turn; and, therefore, to one two-hundred-and-fiftieth of an inch. Hence in reading off the graduations the tens are shown on the body of the whistle, and the units are shown on the edge of the cap.

The scale of the instrument having for its unit the two-hundred-and- fiftieth part of an inch, it follows that the number of vibrations in the note of the whistle is to be found by dividing (13440 x 250)/4 or 84,000, by the graduations read off on its scale.

A short table is annexed, giving the number of vibrations calculated by this formula, for different depths, bearing in mind that the earlier entries cannot be relied upon unless the whistle has a very minute bore, and consequently a very feeble note.

| Scale Readings | Corresponding |
| (one division | Number of |
| = 1/250 | Vibrations |
| of an inch). | per Second |
|—————-+—————-| | 10 | 84,000 |
| 15 | 56,000 |
| 20 | 42,000 |
| 25 | 33,600 |
| 30 | 28,000 |
| 35 | 24,000 |
| 40 | 21,000 |
| 45 | 28,666 |
| 50 | 16,800 |
| 55 | 15,273 |
| 60 | 14,000 |
| 65 | 12,923 |
| 70 | 12,000 |
| 75 | 11,200 |
| 80 | 10,500 |
| 85 | 9,882 |
| 90 | 9,333 |
| 95 | 8,842 |
| 100 | 8,400 |
| 105 | 8,000 |
| 110 | 7,591 |
| 115 | 7,305 |
| 120 | 7,000 |
| 125 | 6,720 |
| 130 | 6,461 |

[Footnote 28: Mr. Hawksley, surgical instrument maker 307 Oxford Street also makes these.]

The largest whistles suitable for experiments on the human ear, have an inner tube of about 0.16 inches in diameter, which is equal to 40 units of the scale. Consequently in these instruments the theory of closed pipes ceases to be trustworthy when the depth of the whistle is less than about 60 units. In short, we cannot be sure of sounding with them a higher note than one of 14,000 vibrations to the second, unless we use tubes of still smaller bore. In some of my experiments I was driven to use very fine tubes indeed, not wider than those little glass tubes that hold the smallest leads for Mordan’s pencils. I have tried without much success to produce a note that should be both shrill and powerful, and correspond to a battery of small whistles, by flattening a piece of brass tube, and passing another sheet of brass up it, and thus forming a whistle the whole width of the sheet, but of very small diameter from front to back. It made a powerful note, but not a very pure one. I also constructed an annular whistle by means of three cylinders, one sliding within the other two, and graduated as before.

When the limits of audibility are approached, the sound becomes much fainter, and when that limit is reached, the sound usually gives place to a peculiar sensation, which is not sound but more like dizziness, and which some persons experience to a high degree. Young people hear shriller sounds than older people, and I am told there is a proverb in Dorsetshire, that no agricultural labourer who is more than forty years old, can hear a bat squeak. The power of hearing shrill notes has nothing to do with sharpness of hearing, any more than a wide range of the key-board of a piano has to do with the sound of the individual strings. We all have our limits, and that limit may be quickly found by these whistles in every case. The facility of hearing shrill sounds depends in some degree on the position of the whistle, for it is highest when it is held exactly opposite the opening of the ear. Any roughness of the lining of the auditory canal appears to have a marked effect in checking the transmission of rapid vibrations when they strike the ear obliquely. I myself feel this in a marked degree, and I have long noted the fact in respect to the buzz of a mosquito. I do not hear the mosquito much as it flies about, but when it passes close by my ear I hear a “ping,” the suddenness of which is very striking. Mr. Dalby, the aurist, to whom I gave one of these instruments, tells me he uses it for diagnoses. When the power of hearing high notes is wholly lost, the loss is commonly owing to failure in the nerves, but when very deaf people are still able to hear high notes if they are sounded with force, the nerves are usually all right, and the fault lies in the lining of the auditory canal.


The Questions that I circulated were as follows; there was an earlier and uncomplete form, which I need not reproduce here.

The object of these Questions is to elicit the degree in which different persons possess the power of seeing images in their mind’s eye, and of reviving past sensations.

From inquiries I have already made, it appears that remarkable variations exist both in the strength and in the quality of these faculties, and it is highly probable that a statistical inquiry into them will throw light upon more than one psychological problem.

Before addressing yourself to any of the Questions on the opposite page, think of some definite object–suppose it is your breakfast-table as you sat down to it this morning–and consider carefully the picture that rises before your mind’s eye.

1. _Illumination_.–Is the image dim or fairly clear? Is its brightness comparable to that of the actual scene?

2. _Definition_.–Are all the objects pretty well defined at the same time, or is the place of sharpest definition at any one moment more contracted than it is in a real scene?

3. _Colouring_.–Are the colours of the china, of the toast, bread crust, mustard, meat, parsley, or whatever may have been on the table, quite distinct and natural?

4. _Extent of field of view_.–Call up the image of some panoramic view (the walls of your room might suffice), can you force yourself to see mentally a wider range of it than could be taken in by any single glance of the eyes? Can you mentally see more than three faces of a die, or more than one hemisphere of a globe at the same instant of time?

5. _Distance of images_.–Where do mental images appear to be situated? within the head, within the eye-ball, just in front of the eyes, or at a distance corresponding to reality? Can you project an image upon a piece of paper?

6. _Command over images_.–Can you retain a mental picture steadily before the eyes? When you do so, does it grow brighter or dimmer? When the act of retaining it becomes wearisome, in what part of the head or eye-ball is the fatigue felt?

7. _Persons_.–Can you recall with distinctness the features of all near relations and many other persons? Can you at will cause your mental image of any or most of them to sit, stand, or turn slowly round? Can you deliberately seat the image of a well-known person in a chair and see it with enough distinctness to enable you to sketch it leisurely (supposing yourself able to draw)?

8. _Scenery_.–Do you preserve the recollection of scenery with much precision of detail, and do you find pleasure in dwelling on it? Can you easily form mental pictures from the descriptions of scenery that are so frequently met with in novels and books of travel?

9. _Comparison with reality_.–What difference do you perceive between a very vivid mental picture called up in the dark, and a real scene? Have you ever mistaken a mental image for a reality when in health and wide awake?

10. _Numerals and dates_.–Are these invariably associated in your mind with any peculiar mental imagery, whether of written or printed figures, diagrams, or colours? If so, explain fully, and say if you can account for the association?

11.–_Specialities_.–If you happen to have special aptitudes for mechanics, mathematics (either geometry of three dimensions or pure analysis), mental arithmetic, or chess-playing blindfold, please explain fully how far your processes depend on the use of visual images, and how far otherwise?

12. Call up before your imagination the objects specified in the six following paragraphs, numbered A to F, and consider carefully whether your mental representation of them generally, is in each group very faint, faint, fair, good, or vivid and comparable to the actual sensation:–

A. _Light and colour_.–An evenly clouded sky (omitting all landscape), first bright, then gloomy. A thick surrounding haze, first white, then successively blue, yellow, green, and red.

B. _Sound_.–The beat of rain against the window panes, the crack of a whip, a church bell, the hum of bees, the whistle of a railway, the clinking of tea-spoons and saucers, the slam of a door.

C. _Smells_.–Tar, roses, an oil-lamp blown out, hay, violets, a fur coat, gas, tobacco.

D. _Tastes_.–Salt, sugar, lemon juice, raisins, chocolate, currant jelly.

E. _Touch_.–Velvet, silk, soap, gum, sand, dough, a crisp dead leaf, the prick of a pin.

F. _Other sensations_.–Heat, hunger, cold, thirst, fatigue, fever, drowsiness, a bad cold.

13. _Music_.–Have you any aptitude for mentally recalling music, or for imagining it?

14. _At different ages_.–Do you recollect what your powers of visualising, etc., were in childhood? Have they varied much within your recollection?

_General remarks_.–Supplementary information written here, or on a separate piece of paper, will be acceptable.


_For an analysis of the several chapters, see Table of Contents._

Abbadie, A. d’
About, E.
Abstract ideas,
like composite portraits;
are formed with difficulty
Admiralty, records of lives of sailors Adoption
captive animals;
races of men
_Alert_, H.M.S.,
the crew of
Alexander the Great,
medals of;
his help to Aristotle
captive animals;
change of population
Animals and birds,
their attachments and aversions
anthropometric committee;
Appold, Mr.
their migrations
his menagerie
(_see also_ Psychometric experiments) Assyria,
captive animals
Athletic feats in present and past generations Augive, or ogive
Austin, A.L.
tame kites;
change of population
Automatic thought

Barclay, Capt.,
of Uri
Barth, Dr.
Bates, W.H.
Baume, Dr.
Belief (_ie_ Faith)
Bevington, Miss L.
Bible, family
Bidder, G.
Blackburne, Mr.
Blake, the artist
Bleuler and Lehman
Blind, the
Blood, terror at
Boisbaudran, Lecoq de
Breaking out (violent passion)
Brierre de Boismont
Bruhl, Prof.
Burton, Capt.
their skill in drawing;
in Damara Land

Campbell, J. (of Islay)
Candidates, selection of
Captive Animals (_see_ Domestication of Animals) Cats can hear very shrill notes
their terror at blood;
gregariousness of;
renders them easy to tend;
cow guarding her newly-born calf;
cattle highly prized by Damaras
Celibacy as a religious exercise;
effect of endowments upon;
to prevent continuance of an inferior race Centesimal grades
Chance, influence of, in test experiments Change, love of, characteristic of civilised man CHARACTER;
observations on at schools;
changing phases of
Charterhouse College
Cheltenham College
Chess, played blindfold
mental imagery;
effect of illness on growth of head; moral impressions on;
they and their parents understand each other; can hear shrill notes
Chinese, the
Clock face, origin of some Number-Forms Colleges, celibacy of Fellows of
(_see_ also chap. on Visionaries); colour blindness
Comfort, love of, a condition of domesticability Competitive examinations
also Memoirs I., II., and III. in Appendix Composite origin of some visions;
of ideas;
of memories
defective in criminals;
its origin
(_see_ Antechamber of);
ignorance of its relation to the unconscious lives of cells of organism; its limited ken
Consumption, types of features connected with Cooper, Miss

criminals, their features;
their peculiarities of character;
their children

Cromwell’s soldiers


colour blindness
was a Quaker

their grade of sensitivity;
their wild cattle and gregariousness; their pride in them;
races of men in Damara Land


Darwin, Charles,
impulse given by him to new lines of thought; on conscience;
notes on twins;
letter of Mr. A. L. Austin forwarded by

Darwin, Lieut., R.E.,
photographs of Royal Engineers


Death, fear of; its orderly occurrence; death and reproduction of
cells, and their unknown relation to consciousness

Despine, Prosper

Difference, verbal difficulty in defining many grades of

Discipline, ascetic

_Discovery_, H.M.S., the crew of

Discrimination of weights by handling them, etc.

Dividualism; also

Doctrines, diversity of

Dogs, their capacity for hearing shrill notes



Du Cane, Sir E.

Duncan, Dr. Mathews





Editors of newspapers

Egg, raw and boiled, when spun

Egypt, captive animals

Ellis, Rev. Mr. (Polynesia)

Emigrants, value of their breed;
migration of barbarian races



Engineers, Royal, features of

English race, change of type; colour
of hair; one direction in which
it might be improved; change
of stature; various components of


Epileptic constitution

Eskimo, faculty of drawing and map-making

Eugenic, definition of the word

Events, observed order of

Evolution, its effects are always behind-hand; its slow progress; man
should deliberately further it

Exiles, families of

Experiments, psychometric

FACES seen in the fire, on wall paper, etc.,


Family likenesses; records; merit,
marks for

Fashion, changes of

Fasting, visions caused by;
fasting girls


Fellows of colleges

Fertility at different ages; is small in highly-bred animals


First Cause, an enigma

Flame, sensitive, and high notes

Fleas are healthful stimuli to animals

Fluency of language and ideas

Forest clearing

Forms in which numerals are seen (_see_ Number-Forms); months; letters;

Foxes, preservation of

France, political persecution in

French, the, imaginative faculty of

Friends, the Society of (_see_ Quakers)


Generations, length of and effect in population; in town and country

Generic images; theory of

Geometric series of test-objects; geometric mean

Gerard, Jules


Gibbon, amphitheatrical shows

Goethe and his visualised rose


Goodwin, Mr.

Grades, deficiency of in language;

Graham, Dr., on idiots (note)

gregariousness of cattle;
gregarious animals quickly learn from one another

Gull, Sir W., on vigour of members of large families; on medical life-histories

Guy’s Hospital Reports (consumptive


HAIR, colour of

Hall, Capt.

Hallucinations, cases of; origin of;
of great men

Handwriting; of twins

Hanwell Asylum, lunatics when at exercise

Hatherley, Lord
Haweis, Mrs.,
words and faces;
Head measured for curve of growth
Hearne (N. America)
Height, comparative, of present and past generation,
Henslow, Rev. G.,
Heredity, the family tie;
of colour blindness in Quakers;
of criminality;
of faculty of visualising;
of seeing Number-Forms;
of colour associations with sound; of seership;
of enthusiasm;
of character and its help in the teaching of children by their parents;
that of a good stock is a valuable patrimony, Hershon, Mr., the Talmud,
Hill, Rev. A.D.,
Hippocrates and snake symbol,
History of twins,
Holland, F.M.,
Hottentots, keenness of sight,
(_see_ Bushmen)
Human Nature, variety of,
Humanity of the future, power of present generation of men upon it,
Hutchinson, Mr.,
Huxley, Professor,
on sucking pigs in New Guinea;
generic images,

Idiots, deficient in energy; in sensitivity, Illness, permanent effect on growth,
Illumination, method of regulating it when making composites;
requires to be controlled,
Illusions, (_see_ also Hallucinations, cases of) Imagery, mental,
Indian Civil Service, candidates for, Individuality, doubt of among the insane, among the sane,
Influence of Man upon race,
Insane, the,
similar forms of it in twins,
Inspiration analogous to ordinary fluency, morbid forms of,
Instincts, variety of,
slavish (_see_ chapter on Gregarious and Slavish Instincts)
Intellectual differences,

Jesuits in S. America,
Jukes, criminal family,

Kensington Gardens, the promenaders in, Key, Dr. J.,
Kingsley, Miss R.,
Kirk, Sir John,

Laboratories, anthropometric,
Larden, W.,
Legros, Prof.,
Lehman and Bleuler, (note)
Letters, association of colour with, Lewis, G.H.,
Lewis, Miss,
Life-histories, their importance,
Livingstone, Dr.,
Longevity of families,

Macalister, Dr.,
M’Leod, Prof. H.,
Madness (_see_ Insanity)
Mahomed, Dr.,
marriage portions,
Man, his influence upon race,
Mann, Dr.,
Marks for family merit,
Marlborough College,
early and late,
with persons of good race;
marriage portions;
of Fellows of Colleges;
promotion of,
Medians and quartiles,
physiological basis of;
confusion of separate memories,
Mental imagery,
Meredith, Mrs.,
Milk offered by she-goats and wolves to children, Moors, migrations of the,
Moreau, Dr. J. (of Tours),
Morphy, P.,
Muscular and accompanying senses, tests of, Mussulmans,
small fear of death;
things clean and unclean,

Namaquas in Damara Land,
(_see_ also Bushmen)
Napoleon I.,
views in connection with the
faculty of visualising;
his star,
Nature (_see_ Nurture and Nature)
Negro displaced by Berbers;
by Bushmen;
exported as slaves;
replaceable by Chinese,
Nervous irritability, as distinct from sensitivity, New Guinea,
Nicholson, Sir C.,
Notes, audibility of very shrill,
Nourse, Prof. J.E.,
Numerals, their nomenclature;
characters assigned to them;
Nurture and nature;
history of twins,
Nussbaumer, brothers,

Observed order of events,
Ogive (statistical curve)

Osborn, Mr.
Osten Sacken, Baron v.
Oswell, Mr.
Oxen (_see_ Cattle)

Parkyns, Mansfield
Peculiarities, unconsciousness of
Persecution, its effect on the character of races Peru, captive animals in
Pet animals
Petrie, Flinders
Photographic composites (_see_ Composite Portraiture); registers;
summed effect of a thousand brief exposures; order of exposure is indifferent
Phthisis, typical features of
Piety, morbid forms of, in the epileptic and insane; in the hysterical
Polynesia, pet eels
Ponies, their capacity for hearing shrill notes Poole, R. Stuart
Poole, W.H.
population in town and country;
changes of;
decays of;
effects of early marriages on
Portraits, composite (_see_ Composite Portraiture); number of elements in a portrait;
the National Portrait Gallery
Prejudices instilled by doctrinal teachers; affect the judgments of able men
Presence-chamber in mind
Pricker for statistical records
Princeton College, U.S.
Prisms, double image
Proudfoot, Mr.
Psychometric experiments

Quakers, frequency of colour blindness Quartiles
Questions on visualising and other allied faculties Quetelet

Race and Selection;
influence of man upon;
variety and number of races in different countries; sexual apathy of decaying races;
signs of superior race;
pride in being of good race
Races established to discover the best horses to breed from Rapp, General
Rapture, religious
Rayleigh, Lord, sensitive flame and high notes Reindeer, difficulty of taming
Republic of self-reliant men;
of life generally;
Revivals, religious
Richardson, Sir John
Roberts, C. (note)
Roget, J.
Rome, wild animals captured for use of Rosiere, marriage portion to

Sailors, keenness of eyesight tested; admiralty life-histories of
_St. James’s Gazette_ (Phantasmagoria) Savages, eyesight of
Schools, biographical notes at;
opportunities of masters;
observation of characters at
Schuster, Prof.
Seal in pond, a simile;
captured and tamed
Seemann, Dr.
Seers (_see_ chapter on Visionaries); heredity of
Segregation, passionate terror at among cattle Selection and race
Self, becoming less personal
Sentiments, early
Sequence of test weights
Serpent worship
Servility (_see_ Gregarious and Slavish Instincts); its romantic side
Sexual differences in sensitivity;
in character;
apathy in highly-bred animals
Siberia, change of population in
Slavishness (_see_ Gregarious and Slavish Instincts) Smith, B. Woodd;
curious Number-Form communicated by Smythe, G.F.
Snakes, horror of some persons at;
antipathy to, not common among mankind Socrates and his catalepsy
Sound, association of colour with
Space and time
Spain, the races in
Speke, Capt.
Spencer, H., blended outlines
Spiritual sense, the
Stars of great men
Statistical methods;
statistical constancy;
that of republics of self-reliant men; statistics of mental imagery;
pictorial statistics
Stature of the English
Steinitz, Mr.
Stones, Miss
Stow, Mr.
Suna, his menagerie

Talbot Fox
Talmud, frequency of the different numerals in Tameness, learned when young;
tame cattle preserved to breed from Tastes, changes in
Terror at snakes;
at blood;
is easily taught
Test objects, weights, etc.
Time and space
Town and country population
Trousseau, Dr.
Turner, the painter
Twins, the history of
Typical centre

Unclean, the, and the clean
Unconcsciousness of peculiarities;
in visionaries

Variety of human nature
visionary families and races

Watches, magnetised
Welch, Mrs. Kempe
West Indies, change, of population in Wheel and barrel
Whistles for audibility of shrill notes Wildness taught young
Wilkes, Capt.
Winchester College
Wollaston, Dr.
Wolves, children suckled by
Women, relative sensitivity of;
coyness and caprice;
visualising faculty
Woodfield, Mr. (Australia)
Words, visualised pictures associated with Workers, solitary

Young, Dr.
Yule, Colonel

Zebras, hard to tame
Zoological Gardens, whistles tried at; snakes fed;
seal at
Zukertort, Mr.