Class X.] INSTRUMENTS FOR THE BLIND—COUNT DUNIN’S HUMAN FIGURE.
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Schii.t (Switzerland , No. 59, p. 1270) exhibits a simplecalculating machine, hut which can perform the first |operation of arithmetic only. Honourable Mention wasvoted to Mr. Schilt.
Hooker (No. 340, p. 44S) has exhibited a sliding scale ofinvolution, the invention of Dr. Koget. The instrumentconsists of one fixed and one moveable scale, like a slidingrule. On the slide a line is logometrically divided, thedivisions of one half being from 1 to 10, and repeated onthe second half in the same order.
The fixed scale is graduated in such manner, that eachof its own divisions is set against its respective logarithmon the slider, and, consequently, all the numbers on theslider will be situated immediately under those numbersin the fixed scale, of which they are the logarithms.Thus, 3 on the fixed scale will stand under 100 on therule, and so on.
The instrument is adapted to perform the operations ofinvolution and evolution. The principle of the instru-ment is contained in the equation—
Log. log. a x — log. log. a = log. x.
rom the first member of which a disappears. Twodifferences of the second logarithms of the power and ofthe root being equal to the first logarithms of the index,it is evident, that if a scale of second logarithms beengraved on one line, and a first on a line sliding along it,the indexes being read otf on the latter, the power willbe so on the former.*
Lalaxxe (France , No. 1690) exhibits a calculatingrule, constructed upon new principles, consisting of agraphic table formed entirely of right lines, with whichall calculations, usually performed by the sliding rule, canbe performed to within 1 -200th of the true result. TheJury awarded Honourable Mention to this Exhibitor.
Instruments for the use of the Blind.
Hughes (No. 401, p. 452) has exhibited a portabletypograph or writing machine for the blind.
This is a beautiful mechanical contrivance (by nomeans difficult in use) by which a blind person is enabledto print legibly, with ease and rapidity. It is also appli-cable to printing uniform labels for Museums, &c. (fordescription see “ Illustrated Catalogue”). The followingis the maimer of using it. The paper intended to bewritten upon is placed within a portfolio, one side ofwhich is made of semi-carbonized paper, which, beingdurable and inexpensive, serves for ink. Having donethis with the first finger of the right hand, any requiredletter, figure, or point of the index circle is brought tothe right side of the lever, the thumb being inserted inthe end of which, presses it downwards. This pressurewill give the impression of a corresponding type letteracting upon the back of the transfer paper. The nextoperation is to lift the lever to its utmost height, whichmotion makes the space required for the next letter, andso on to the end of a word. A repetition of the move-ment will also make the space between the words.
Having finished a line of writing, the index circle ispushed back to the left side of its frame, and the thumb-screw turned for the desired distance between the lines;one whole turn of this screw giving four lines to theinch.
The typograph is about the size of a quarto booh, anddoes not occupy a surface of more than 12 inches square.Its inventor has done good service, having the merit ofexhibiting the best machine for the same purpose, it beingthe most simple in its operations of any in the Exhibition.The Piize Medal was awarded to Mr. Hughes.
Tollputt (No. 382, p. 451) exhibits a machine forfacilitating the writing of the blind.
Foucault (France, No. 220a, p. 1187) has exhibited aprinting-machine for the blind. It consists of a fan com-posed of 26 rods, terminated at the upper extremity withthe letters of the alphabet arranged successively, togetherwith other rods terminated with the various ciphers andsymbols required in printing; the lower extremity ofthese rods is furnished with a corresponding letter, &c., to
* See “Philosophical Transactions M for the year 1815.
the one above, but in smaller type. On pressing thelarger character at the upper extremity, the smaller letterbeneath is proportionably depressed, which causes it toleave its printed impression on a paper previously pre-pared. By a little contrivance the paper is made to moveonwards, in proportion to the successive pressures fromabove. The exhibitor of this machine, himself blind, liasthe merit of being its inventor, and he was awarded thePrize Medal.
Thompson' (United States , No. 26, p. 1434) has exhi-bited an invention for teaching the blind to draw andwrite. This device is simple, and intended to afford ameans to the blind of acquiring knowledge of variouskinds.
The writing tablet is covered with white leather, amaterial well suited to the purpose intended, as it yieldsto the pressure of the style without retaining the im-pression.
The style may he made of any hard material capable ofreceiving and retaining a rounded smooth point. Thepaper should be of a strong and rather firm texture, butat no visit of the Jury was any explanation given, andthey are unable to speak further of this invention.
Gall (No. GS7a, p. 471*) has exhibited a triangularalphabet for the blind. This is an improvement on theParisian, Austrian , and other circular alphabets, and it isprobable that adult blind persons may by its means beeasily taught to read. A volume containing the Epistleto the Ephesians, in the same characters, was exhibited,and Gall’s apparatus for the writing of the blind, bymeans of which they can correspond with each other bypost, as described in the “ Illustrated Catalogue.”
Marchesi (Austria, No. 139, p. 1049,) exhibits a cir-cular printing machine, by which the blind can printreadily with three different kinds of type. On examina-tion by the Jury it elicited much commendation, and aPrize Medal was awarded to M. Marchesi.
Miscellaneous.
Dunin (No. 210, pp. 433, 434) has exhibited a piece ofmechanism designed to illustrate the different proportionsof the human figure. This beautiful piece of mechanismresembles in outward appearance a well-formed humanfigure, standing erect, it is capable of both considerableexpansion and contraction in all its parts. The internalmechanism is completely concealed, the figure externallybeing composed of a number of thin slips of steel andcopper, which overlap each other in proportion to theamount of expansion or contraction exercised. Themotion these slips are made to possess is communicated tothem by thin metal slides to which they are attachedwithin the figure, the slides being furnished with project-ing pins at their extremities. These pins are insertedinto curved grooves, cut in circular steel plates, the cur-vature of the grooves being so arranged, that when thesteel plates are put in revolution by a train of wheels andscrews, the slides belonging to the several parts of thefigure are expanded or contracted in correct proportion.The external slips of metal are disposed as much as pos-sible in the direction of the fibres of the muscles in theliving subject, in which direction the two motions of con-traction and expansion aie severally performed. Wherein nature the fibres of the pectoral muscle convergetowards the shoulder, in the figure there is much com-pound internal mechanism, and very ingenious externalarrangement; the contraction of the chest, the back, theshoulder, and the fore-ami, are performed either simul-taneously, with great accuracy and just proportion, oreach part can be separately adjusted if required. Theseadjustments, the most compound and difficult to he over-come, Count Dunin; by a new and most ingenious combi-nation of mechanism, has successfully achieved. Thedimensions of the figure are subjected to their respectivevariations by the establishment of a connection betweenseveral parts of the internal mechanism and a windingkev, by means of circular-headed projections, which beingturned to the right or left, gently and gradually effect thecontraction or expansion of the adjacent parts of thefigure. The motions we have just described, are per-formed by the introduction of the winding key into several