obliquely outwards, by whose reaction, as the wind issues,it appeal's to be the inventor’s design to impel and toguide the balloon.
Mason 'No. 714, p. 474*) has exhibited the model of anavigable balloon, to be worked and directed by means ofsails, helm, and mariner’s compass. The mode! exhibitedis upon a scale of a quarter of an inch to a foot. Fromwhat may be regarded as its after part, project laterallyaxles, giving a rotary motion to sails of the nature ofscrew-propellers.
Plummer (No. 710, p. 474*) has exhibited the workingmodel of an aerial machine, furnished with wings or sails,put in motion by a clock-spring.
Calculating Machines.
There have been very many attempts to perform nume-rical calculations by mechanical means, or at least suchparts of them as follow simple and rigid laws. Hithertosuch instruments have failed to unite correctness in theresults, combined with economy of time, and, for themost part, have been limited to the performance of thefirst two operations of arithmetic.
To make such instruments really useful, they musthave the power of executing, by themselves, the successiveoperations for the solution of the problem imposed onthem, when the simple data for this problem have beenintroduced, without trial, and without guess-work.
The best machine of this kind exhibited is that ofStatFel (Russia , 148), which, on examination, seems tocombine accuracy with economy of time, and workseasily and directly. The mechanism is 18 inches inlength, 9 inches in breadth, and 4 inches in height, andconsists of three rows of vertical cylinders; the firstcontains 13, the second 7, and the third 7. Upon eachof the cylinders in the first row are 10 notches, corre-sponding with the units 1 to 10. Within each of thesecylinders is a small pulley, in connection with a lever,set in motion by a slider which, when the cylinder hasbeen turned from either 9 to 0, or 0 to 9, sets in motionthe lever, and communicates its action to wheels, whichcarry over the ligures. The pulley connected with thecylinder, the furthest from the handle, is in connectionwith the hammer of a bell. The purpose of this bell is togive warning to the operator, on committing an error,aud constitutes a most important addition to the machine,particularly in the operation of division.
Upon each of the cylinders in the second row 10 unitsare placed. These seven cylinders are so fixed upontheir axes, that they can bodily be moved right and left,and fixed at any part, so that the cyphers in the twocylinders can be made to correspond. This cylinder isfurnished with a spike, which lays hold of and works thethird row of cylinders.
The internal communication of each of the parts isbrought about by means of a connecting wheel, furnishedwith nine moveable pegs, which are set in motion bymeans of an eccentric incision in the dial.
The machine is capable of performing addition, sub-traction, multiplication, division, and of extracting thesquare root.
The operation of addition is performed as follows:—■
By simply placing one line of the numbers upon thesecond row of cylinders (the index pointing to addition),aud turning the handle, till it stops, these numbers aretransferred almost instantly to the first row of cylinders,and so on successively, till all the numbers to be addedare transferred, and their sum is shown on the top row.
In performing subtraction, the first part of the operationis the same as in addition, but on placing the second lineof figures on the second row of cylinders, the pointerbeing placed to subtraction, the handle is turned theopposite way, or against the motion of the sun, and thedifference of the two numbers is shown on the upperline.
The operation of multiplication is performed by placingthe multiplier and the multiplicand on the second andthird rows of cylinders, and then, the index pointing tomultiplication, the product will be found on the firstcylinder.
The operation of division is very similar, exceptingthat the handle is turned as in subtraction.
These several operations were performed accurately,and with despatch.
In the performance of the square root, the followingadditional mechanism needs explanation. Between everydivision of the cylinder, in row 2, a small wheel is placed,and near it a projecting piece which acts upon a lever;when the projecting piece is near the word “ rad” engravedon the cylinder, on turning the handle, the figures increaseby 1. This, by other mechanism, is connected with theother two rows of cylinders. The operation of the squareroot is performed directly, without any guessing at num-bers ; but it is, comparatively, rather a long process.
Upon the whole it must be considered that Mr. Staffclhas made au instrument possessed of considerable powers,and that great praise is due to him. The double motionof the handle as well as the warning bell are importantimprovements.
Mr. Statfel also exhibits a small mechanical machinefor the performance of the addition and subtraction offractions, whose denominators are 10 , 12, and 15. Byenlarging the machine, this number would be increased,and the power of the instrument extended. The opera-tions were performed with quickness, and with accurateresults. A Prize Medal was voted to Mr. Staffel.
Thomas de Colmar (France , No. 390, p. 1196) exhibitsthe next best calculating machine in the Exhibition, andhas combined the two essentials of economy of time andaccuracy of results. It is adapted for the performance ofthe four first rules of arithmetic; and indirectly the square-root may be extracted by the knowledge of a i -\-2ab-\-b i ythe results being inferred; but this is not the legitimateuse of the instrument.*
The instrument is adapted for the multiplication ofnumbers whose product is expressed by less than 16 figures;ami consists of two rows of cylinders, the one containing16, and the seconds; the former are moveable, theoperation at each step being changed tenfold.
The principle of the instrument is, that multiplicationis in reality the continual addition of itself as many timesas there are units in the multiplier, and division that ofcontinued subtraction of the divisor.
On trying the machine, the number 1 was almost in-stantaneously taken from 10,000, giving the difference,9,999, accurately; the performance of this operation isgenerally a severe test to these machines.
The number 5,321 was multiplied by 3,256 in less timethan was required to perform the calculation, in themanner following:—The number 5,321 was placed onone senes of cylinders, and the number 6 was placed onone of the cylinders of the second row, and on the handlebeing turned (in one direction always) the number 31,926appeared; the upper row was moved through one division,the handle agained turned, and so on, till in a very shorttime, the number 17,325,176 appeared.
The several operations to which the instrument wassubjected were performed quickly and accurately.
A Prize Medal was voted to M. Thomas De Colmar.
Wertheimer (No. 387, p. 451) exhibits several calcu-lating machines, adapted for the performance of additionand subtraction of numbers and moneys, of this and ofother countries.
Each machine consists of a box, with a metal platedivided into nine indexes, with semicircular notches, underwhich are placed a succession of holes. Round theindexes, numbers are engraved, and the semicircularnotches are furnished with teeth, and a pointer to insertbetween the notches, for the purpose of bringing the notchopposite any particular figure, from right to left. Thisoperation is dangerous, for the notch is liable to slip andnot go home.
The instruments are ingenious, but they are muchwanting in the essentials of such machines, viz., economyof time and unerring accuracy. The Jury, however,voted Honourable Mention to them.
* For a description of this ingenious and useful machine,see the report of M. Benoit, “ Au nom du Comite de9 ArtsMecaniqucs, Socie’te d'Encouragcment.”