Class X.]
261
•with the top of the box: it will hold about 500 sovereigns.In front of the box are two small apertures, to which arefitted two receivers, one for the sovereigns of full weight,the other for those which are light.
Inside the box, and near the upper plate, the beam orbalance is placed; at one end of the beam, and above it,is poised upon a knife-edge, a small platform, which re-ceives the sovereigns to be weighed. This platform,which, in fact, is one of the scales, is kept in its positionby means of a small pendulum, on which, at about aninch below the platform, there is an oblong perforation,about half an inch in length, technically called a slot, inwhich a small ivory rod works freely up and down with-out touching the sides.
Hot ween the slot and the platform a pair of forceps isplaced. From a knife-edge at the other end of the beama small round polished plate is suspended, to which apendulum is fixed, and at its lower part the scale is placedto receive the weight. Above the small round plate,under the top of the box, is fixed an agate with a bluntpoint. When the machine is in motion the small ivoryrod is depressed: this, on touching the bottom of the slot,or opening in the pendulum in which it works, bringsdown the beam on that side, and raises it, of course, onthe other, the weight side, until the small round plate onthat side touches the agate point. The beam is then in ahorizontal position. As soon as this is effected the for-ceps catch hold of the pendulum between the platformand the slot, and hold it firmly. The balance is then ina condition to receive the sovereign, which is shifted fromthe bottom of the pile in the hopper, and brought bymeans of a slide along a channel, just large enough for asovereign of the proper standard gold to pass, but notlarge enough to admit a counterfeit, and deposited uponthe platform. The forceps then let go their hold, theivory rod is gently raised, and if the sovereign happens tobe light that end of the beam rises, and the other endleaves the agate point; but if the sovereign be full weight,the beam remains stationary, and the small plate on theweight end is in contact with the agate point.
When the sovereign is weighed, the operation of its re-moval is very ingenious, and is as follows:—Two boltsare placed at right angles to each other, and on each sideof the platform or scale there is a part cut away to admitof the bolts striking so far into the area of the platformas to remove anything that would nearly fill it. Thesebolts are made to strike at different elevations, the lowerone striking (as to time) a little before the other. If thesovereign be full weight the scale remains down, and thelower bolt knocks it off into the full-weight box. If thesovereign, on the other hand, be light, it rises up, thefirst bolt strikes under and misses it, and the higher boltthen strikes and knocks it off into the light box. Thismachine weighs about thirty-three sovereigns in oneminute. The weights used are of glass, and are adjustedto within the ten-thousandth part of a grain.
It is understood that these machines, since they beganto be used in 1844, have not cost £5 for repairs, and thatthey effect a saving in salaries alone of full £1,500 perannum, after deducting ten per cent, for the replacementof capital sunk in their establishment.
A Prize Medal was awarded to Mr. Cotton .
Smith (India) has exhibited a coin-weighing machine,which is an exceedingly ingenious application of that ofthe areaometer or hydrostatic balance. The counterpoiseto the point weight of the scale-pan and coin is made torise and fall in a cylinder of water, the oscillation beingdeadened by a circular plate forming part of the counter-poise wholly immersed in the fluid, and of such an areaas to afford considerable resistance to the rising or sinkingmotion. By a proper adjustment of the diameter of thatportion of the counterpoise which is partly beneath andpartly above water, and of the length of the lever armwhich carries the scale-pan, a given deviation in theweight of the coin oneway or other from its legal weightmay be made to correspond with a given depression or ele-vation of the counterpoise, and therefore of the scale-pan,below or above a certain medium or zero position, the scaleresting at a level, corresponding to the amount of excessor defect of the coin above or below the standard.
I At levels corresponding to half grains of difference ofweight, shelves are placed which receive the coins fromthe scale-pan, according as, on arriving at its point ofequilibrium, it happens to be opposite to the iuterval be-tween either shelf and the next above it; and once thrownupon tliat shelf, it glides down and finds its way into areceptacle corresponding by an appropriate passage. Thusthe coins enter twelve panels, differing each by twelvegrains of weight.
To throw the coin off the scale upon its proper shelf,the scale-pan is peculiarly constructed of wire, horizon-tally laid, so as to allow a scraper, also of wire, verticallyarranged, to pass between and beside the frame-work ofthe pau, which, being pushed along at the end of eachweighing, the coin is forced by it off the pan upon theshelf. The pan-frame, thus lightened, rises to the properposition for receiving another coin, which is placed on itby a feeding-pipe in the manner usual in coining pro-cesses.
Any number of small weighing-machines may bemounted side by side, so as to occupy a very moderatecompass, and may be worked simultaneously by a commonfeeding and a common discharging movement; and allmay be made to discharge their contents on the sameshelves conducting to common receptacles.* A PrizeMedal was awarded to Captain Smith .
Delkuil (France , No. 100, pp. 1178—11S0) exhibits abeautiful coin-weighing machine, invented by BaronSeguier, Membre de PAcademie des Sciences, differing,however, from those above described in its mechanicalarrangements, and in some particulars of constructionwhich are necessary to its performance of the additionaloperation required by the French Bank .
In the Bank of France each piece of money is weighedin a small balance, especially constructed for the purpose,by men charged with this particular duty. The beautifulcoin-weighing machine in question is designed to super-sede this work by mechanical means. In its working itexhibits quickness and regularity in performing the opera-tion of distributing the pieces into three classes, thosewhich are heavy, those which are of exact weight, andthose which are light.
The instrument is distinguished in its operations fromMr. Cotton ’s, by thus distributing the pieces into threeclasses instead of two, as in Mr. Cotton ’s, the three beingnecessary in the Bank of France , though not requiredin England.
The right to this elegant invention not being securedby a patent, its internal construction could not be ex-amined; but so far as could be judged from working it,as exhibited, the principle seems to be the making avail-able the declination of the index of the balance, or lightsteel rod, to the right or left of the vertical, according tothe excess of weight in either pan, to give motion to oneor other of two light brass plates in the act of raising thebalance. The force so applied being, not the mere dif-ference of weights between the scales, but an externalpower applied through this medium; the motion thusgiven to the brass plate being conveyed downwards by anappropriate train of mechanism might easily he applied toan interposed obstacle or otherwise. The coin, on itsdelivery from the scale, is diverted from that passagewhich it would have followed had the index remainedvertical, into one of two other channels according to theinclination of the index.
The machine is fed by a hopper, the coin being thrownpromiscuously in. To prevent its jamming, and refusingto pass, it is constantly stirred from below upwards by awheel set round with steel pins so as to disturb ihe self-arrangement of the coins in the hopper, and let themfall over one by one into the feeding-trough. It is un-derstood that about fifty coins could be weighed perminute by a double machine, such as that exhibited.The working appeared to be not quite continuous, but inall other respects perfectly satisfactory, the interruption