« EelmineJätka »
Fig. 2. The board was thin and smooth, and rather more than a foot square; fixed in a narrow frame slightly raised above it, containing a great number of cross parallel lines drawn at right angles to each other. The edges of the board had grooves about two inches apart, and to each groove belong five parallels, each square inch being subdivided into one hundred smaller squares. At every point of intersection was a small hole, to receive a peg or pin. Saunderson always kept two boxes of pins by his side when at work, and these, by difference of position or head, expressed to him the various numerals; a larger peg in the centre of each little square standing for zero, a smaller one for 1. The other numerals stand thus
and were at once detected by their relative position
to the central 0 or 1, the greater pegs (for 0) being all
always in their place when not needed forl; serving ** him for guides to preserve his line of figures and
to prevent other mistakes. Saunderson placed and
displaced the pins with inconceivable quickness, but the exact way in which
he used them in performing his arithmetical calculations is altogether a mystery. We imagine that by far the larger portion of his work must have been done mentally, and that he used groups of pins from time to time, in certain relative positions, to express certain stages in the operation, as memoranda to which he could refer again and again with a touch, and thus verify his work. Be this as it may, however, there is no doubt that he worked problems of every possible kind, both in common arithmetic, fractions, decimals, or algebra, with great rapidity and equal accuracy. A glance at that part of the board marked Fig. 1 will show how easily he adapted it for the working of geometrical problems by placing pins at the angular points, and surrounding them with a silk thread, so as to form any figure which he required. Genius as he was, and full of resources which genius alone can devise and use, he would doubtless have rejoiced to possess one of the plain and simple arithmetic boards now in use at St. George's Fields. *
Embossing a letter is a far easier task than a sum in arithmetic, and the horrors of spelling are less than those of Long Division. When once a boy has learned to read a chapter of Robinson Crusoe in Alston's type (the Roman letter), he is very soon able to write home and tell of his accomplishments. The process is just like that which children call pricking a pattern in paper, except that instead of being managed with a single pinpoint, an entire letter of pin-points is pierced by one single pressure. The embossing frame consists of two parts, one a plain slab of wood about 14 inches long by 8 wide, covered on one side with a thick layer of flannel or velvet; and the other of a plain framework of horizontal bars about half an inch apart; the two being connected by hinges which join them together as a slip of leather does the two covers of a book. When the blind boy wishes to write a letter, he lays his sheet of paper on side 2, and folds over upon it side 1, through the bars of which he presses small wooden types, each bearing on one end a Roman letter formed of projecting pin-points. These he forces steadily home through the paper into the flannel or leather below, placing each letter as he does so the reverse way, so as to make the embossing correct on the other side of the paper. The process is a slow one, as every letter has to
* Saunderson, with all his cleverness, was never able to write.
: be be separately stamped down and held in its place till its next neighbour is introduced, that not a grain of precious space be wasted ; but at last, duly reversed and in good order, appear the pleasant words, MY DEAR EATHER And proud enough, we may well imagine, is Sam Trotter, the village blacksmith, when he gets his first letter from our blind Johnny in London; it goes the round of the whole community, and in spite of some grievous lapses in orthography, is fairly worn out at last with continual handling, unless locked up by the good wife as too precious a document for the perusal of ordinary mortals. Their wonder will be doubled when Johnny comes home next year at the Midsummer holidays, and reads off his own epistle with the tips of his fingers.
The weaver sets to work with a loom of the ordinary kind, which we therefore need not describe, and the only problem is, how shall the blind workman accurately follow a pattern of which he cannot see a single step, in colours which he cannot distinguish. We pause only for a moment, by the way, to notice one common and popular error still afloat, viz., that some clever blind people have the power of detecting colours by the touch. All we can say is, that those who have had the experience of many years, and opportunities for the personal examination of many hundreds of blind persons, of all ages and ranks, including some of remarkable ability, have not been able to find the remotest trace of such a power. There is no more resemblance now between sounds and colours* than in the time of Guillié, fifty years ago; so that no description will enable a blind man to discern between a crimson poppy and the azure corn-flower ; nor can there be any perceptible difference of texture in one morsel of wool, paper, cloth, or feather stained red, and another of grassy green. Dr. Moyes, indeed, who lost his sight at three years of age, says that red gave him a disagreeable sensation, like the touch of a saw,t' and that as other colours became less intense they decreased in harshness, until green conveyed to him an idea like that which he felt in passing his hand over a polished surface. But we suspect that Dr. Moyes was only trying to rival the happy shot of another blind man, who, says Locke, declared that scarlet was to him like the sound of a trumpet.' Trumpets and scarlet go well together, and were
perhaps even more frequently heard of and met with seventy or eighty years ago than they are now, and the name of one might well suggest the other.*
Touch, therefore, which can do so much for the blind workman, can do nothing for him here; but nevertheless, as the Great Exhibition proved, he can weave you a rug bright with all the colours of the rainbow, exactly after the pattern which you prescribe: scroll-work, leaves, fruit, flowers, lozenges, stars, or crossbars. In the first place, his threads of wool are all placed for him by his side, in one exact order, say white, crimson, blue, yellow, and maroon. They are always in the same order and place, so that he takes up whichever he needs with unerring certainty. Hung up to the beam in front of him, but easily within reach of his fingers, is a square of smooth, thin deal, on which is traced the pattern of his rug in nails with heads of every possible variety of shape-round, square, diamond-shape, or triangular ; tacks, brads, and buttons ; some driven home to the surface of the board, others raised one-tenth of an inch above it; but all telling their own story of red, green, white or blue. The board is ruled thus with cross-bar lines, and at every point of
intersection a small hole is bored, into which is slipped a nail with its head square, round, or triangular, as the pattern requires. The boy reads his pattern along the horizontal lines from left to right, and according to the teaching of the nails weaves in the gay scroll-work of brilliant colours as deftly as if he saw every tint. A glance at the above cut will show the first line of a nail pattern; O standing for red, for white, for blue, • for maroon, and x for green; for the arrangement of which in due order the weaver has of course to depend on his teacher with eyes. But if his touch is keen, and his finger not hardened by work, his pattern can be set for him in a far easier and simpler shape by the help of a few embossed letters and figures on a sheet of thick paper. The line of nails in the above cut translated into letters, would run thus, B standing for red, D for white, C for blue, A for maroon, and R for green :B.3 :D.1. C.1. B.1. C.2. B.2. D.1. B.4. A.2. D.1. C.4. B.2. A.7. R.3.*
* A 'pupil of Guillie's, at the Paris Blind School, translated rubente dextera, from Horace's Second Ode, by 'flaming right hand.' Being pressed to translate literally, he gave as an equivalent 'red. When asked what he meant by 'a red arm,' he said that he did not think, like Locke's blind man, that the colour red was like the sound of a trumpet, but he had translated it 'flaming,' because he had been told that fire was red; whence he concluded that heat is accompanied by redness; which determined him to mark the anger of Jupiter by the epithet flaming, because when irritated one is hot, and when hot one must be red.
These letters and figures the blind weaver quickly reads with his finger ; and then readily takes from his row of arranged colours the number of threads or strands requisite to bring to light those curious flowers that grow in the meadows of carpetland; or the still more curious squares, triangles, lozenges, curves, and scrolls, that crop out among the blossoms; weaving on, unconsciously, yet correctly in the dark, with quiet, patient, skill that well deserves the word of praise from his teacher for which he gladly looks.
Touch, then, does much for the blind boy, but brings him not a single grain nearer to the discerning of colours. As the eye of the deaf mute can never hear, so the fingers of the blind will never see. The cessation of resistance may be to the touch of a blind boy what the cessation of colour is to the eye of the seeing ;'t but it was no mean authority who said, “Nihil est in intellectu quod non prius fuerit in sensu,' and the words apply with clouble force in the present instance. Where, therefore, touch fails him, he can gain little external help, and may presently be altogether at sea. Things apparently identical in form may differ in size, and differing in size, may also totally differ in essence and in nature; and of this difference he may be wholly unconscious. He may form, and does form, the most outrageously incorrect | ideas on some common matters, though he may continually amuse and surprise you by clever guesses, or glcains of what seems like intuition. Du Puiseaux, the son of a Professor of Philosophy in the University of Paris, was in
* This ingenious system is the invention of Mr. Matthew Morgan. + Guillie, p. 73.
1 Locke, Condillac, and Molineux, disputed warmly whether a man restored to sight could distinguish a cube from a globe with his eye, although he might have done so by touch when blind. Locke thought that he could not, the fact being that the power of vision in such cases is extremely faulty, and has to be regularly educated till it gradually becomes accurate and trustworthy.
A prodigions variety of sensations, says Sydney Smith, which we suppose we derive from the eye, are really derived from the touch. We can neither see the distance of any object, nor its size, nor figure. The eye originally sees nothing but surtice and colour.'— Lectures on Moral Philosophy, p. 64.