Class V.]
WEIGHING MACHINES—AWARDS.
191
is carried round by the drum a without resistance; thereis, therefore, no deflection of the spring, and no turningof the pulley upon the axis consequent upon that deflec-tion. The trace of the pencil upon the paper will, underthese circumstances, be a straight line; and in all expe-riments the pencil is made first to trace such a line.
When, however, the strap is replaced, and the work isput on the drum n, the latter turns upon its axis, pressingthe spring upon the knife edge, and deflecting it until itsresistance is equal to that opposed by the machine drivenby the strap. By this turning of the drum the pencil ismoved at right angles to the line which it before tracedon the strip of paper, by a space proportional to thedeflection of the spring, and, therefore, to the pressure bywhich the spring is deflected ; and this proportion beingmaintained, however the pressure may be varied, anirregular curved line is traced upon the paper, whosedistance from the straight line before traced upon it, isalways proportional to the pressure by which the machineis driven: whilst the corresponding distance along thestraight line previously drawn, being measured from thecommencement of the motion, is proportional to the spacedescribed by the point of application of that pressure.Hence it is apparent that, as in the case of the commonsteam-indicator, the area of the curvilinear space betweenthe straight line traced by the style before the work wasput on, and the curved line traced by it afterwards, isproportional to the work done in driving it. There aretwo other contrivances worthy of notice.
1st. A contrivance for correcting the want of uniformityin the motion of the paper, produced by the diminutionof the diameter of the roller r, as more of the paperwinds off it. This correction is rendered necessary bythe great length sometimes given to the strip of paper.This correction is effected by the intervention of a fusee-wheel.
2nd. An admirable method of M. Poncelet for regis-tering in numbers in one part of the dynamometer thework which in another (as described above) is registered,under the form of a curvilinear area. This is effected ona principle, which has also been applied to the mechanicalquadrature of areas, in an instrument called the plani-meter, of which several are exhibited in the department ofPhilosophical Instruments. The two registrations serveto verify one another.
Awards in* Section G.
No. 1151,p.l233(France ). P. Clair, 93RnedeChercheMidi, Paris . 1. MM. Poncelet aud Morin’s rotary dyna-mometer. 2. Lapointe’s constant indicator. 3. Clair’sindicator. The award is made for good and intelligentworkmanship in the construction of these machines, underthe direction of MM. Poncelet and Morin. Among thearticles exhibited by M. Clair is also an admirably con-structed model of a locomotive engine in metal, the work-ing parts of which are opened or shown in section, forexplanation and instruction.
No. 761, p. 1216 (France ). J. Beranger and Co.,Lyons. Scales , weighing-machines, and various other im-plements for weighing. Guided by an ingenious mathe-matical theorem, M. Beranger has so combined a systemof levers that he can place one of his scale-pans at anydistance from the other—according to the form he wishesto give to his weighing-machine—without affecting theequality of weights which balance in the two scale-pans.
This combination of levers is simple, economical, com-pact, and admits of a ready application to all purposes ofcommerce. M. Beranger has, in fact, made that appli-cation in the collection of convenient and ornamentalweighing-machines which he exhibits.
No. 944, p. 1225 (France ). Parent, 33 Rue des Arcs,Paris . 'Weighing-scales, weights, and measures, whichhave many of the more important characteristics of in-
struments made for philosophical and chemical purposes,and a degree of precision and accuracy is thus attainablefor the purposes of commerce, which is not to he looked forin common balances. The award is made for an attemptto improve commercial balances, and for the admirableworkmanship of those exhibited.
No. 105, p. 1013 (Austria). H. D. Schmidt, Vienna .Model of a patent weighing table.
The mode of suspending the platform on a quadruplelever, and of connecting this lever with the steelyard, isthe same as usual. But a very advantageous arrangementis made for relieving the steel fulcra of the levers, whenthe machine is not in use, from the weight of the plat-form, and of any carriages passing over it. L’nder thepoints where the platform rests are the four levers; theselevers have stout projections or bosses projecting down-wards, and nearly touching the upper surfaces of fourshort pillars of iron fixed into the masonry at the bottomof the pit. When the machine is not required for weigh-ing, the long end of the lever is lowered, together withthe steelyard counterpoise and framework, by mcaus of awinch and seiew, until the bosses of the levers rest onthe pillars beneath them. The weight of the platformand any carriage upon it is then borne by these pillars,and not by the steel fulcra of the fourfold levers. Thesefulcra are thus saved from much unnecessary deteriora-tion. On raising the frame with the steelyard and theend of the long lever, the weight of the platform isthrown on its fulcra, and the machine is then ready foruse.
No. 774, p. 252. Jonathan Davidson and Co., BaronyStreet, Edinburgh , Inveutors and Manufacturers. Thesteelyards and weighing-machines of these exhibitors aremanufactured in a very creditable manner. The partsappear well proportioned; and care has been taken toprevent deterioration, as far as possible, by applying steelat all the points peculiarly exposed to wear. The arm ofthe steelyard is truly balanced on the fulcrum, and ismarked off in equal divisions. Hence the scale is avail-able for any counterpoise, as the several weights readoff merely show multiples or sub-multiples of the coun-terpoise. The arrangements and proportions of theseveral parts are judiciously determined, aud the whole iswell finished.
No. 784, p 253. II. Pooley and Son, Liverpool, In-ventor and Manufacturer. Patent weighing-machines.These are remarkable for simplicity, neat and effectiveconstruction, and good "workmanship. The principle isalike in all. The weighing platform rests on four points,very near the fulcra of a quadruple lever, as in the commonstreet weighing-machine. One of these fourfold levers isprolonged, and at its extremity is connected with theshort end of the lever, to which the scale-pan with itsweights, or the sliding counterpoise, is attached.
The locomotive weighing-machine appears very de-serving of notice. This consists of a system of threesuch tables, placed so that a locomotive running over themmay have each pair of its wheels on a separate table.Then the three counterpoises may be adjusted until eachone correctly balances the proportion of the weight bear-ing on its table. A bar with a light lever, and a handleprojecting from it over each steelyard, enables theattendant, standing opposite the centre one, to check thevibrations of all three, and inspect with accuracy the stateof adjustment. By the use of this multiplied weighing-machine the proportion of weight borne by each pair ofwheels may be tested, and the inquirer is thus enabled toalter the adjustment of the springs until he has securedsuch a distribution of the load as may be most likely tolead to good working.
No. 772, p. 252. Day and Milliard, 118 SuffolkStreet, Birmingham . Patent weighing-machines. Theaward is made for simplicity of construction and cheapness,
Wandsworth , October 1851.
HENRY MOSELEY, M.A„ Reporter.