Part 27

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.

D.--WHISTLES FOR TESTING THE UPPER LIMITS OF AUDIBLE SOUND IN DIFFERENT INDIVIDUALS.

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.

E.--QUESTIONS ON VISUALISING AND OTHER ALLIED FACULTIES.

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.

INDEX

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

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

Barclay, Capt., of Uri Barrel 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 BODILY QUALITIES Boisbaudran, Lecoq de Breaking out (violent passion) Brierre de Boismont Bruhl, Prof. Burton, Capt. Bushmen, 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 Cattle, 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; prudential; 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 Children, mental imagery; associations; 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 COLOUR ASSOCIATIONS (_see_ also chap. on Visionaries); colour blindness Comfort, love of, a condition of domesticability Competitive examinations COMPOSITE PORTRAITURE; also Memoirs I., II., and III. in Appendix Composite origin of some visions; of ideas; of memories Composition, automatic; literary CONCLUSION Conscience, defective in criminals; its origin Consciousness (_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 AND THE INSANE; criminals, their features; their peculiarities of character; their children

Cromwell's soldiers

Cuckoo

DALTON, colour blindness was a Quaker

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

Dante

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

Deaf-mutes

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

DOMESTICATION OF ANIMALS

Dreaming

Du Cane, Sir E.

Duncan, Dr. Mathews

EARLSWOOD ASYLUM for idiots

EARLY AND LATE MARRIAGES

EARLY SENTIMENTS

Ecstasy

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

ENDOWMENTS

ENERGY

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

ENTHUSIASM

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.,

Faith

Family likenesses; records; merit, marks for

Fashion, changes of

Fasting, visions caused by; fasting girls

FEATURES

Fellows of colleges

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

Fire-faces

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; dates

Foxes, preservation of

France, political persecution in

French, the, imaginative faculty of

Friends, the Society of (_see_ Quakers)

GARCILASSO DE LA VEGA

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

Generic images; theory of

Geometric series of test-objects; geometric mean

Gerard, Jules

Gesture-language

Gibbon, amphitheatrical shows

Goethe and his visualised rose

Gomara

Goodwin, Mr.

Grades, deficiency of in language; centesimal

Graham, Dr., on idiots (note)

GREGARIOUS AND SLAVISH INSTINCTS; 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 types)

Gypsies

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; visions, Head measured for curve of growth Hearne (N. America) Height, comparative, of present and past generation, Henslow, Rev. G., imagery; Number-Forms; visions, 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, Holbein, 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, Hysteria,