TBANSACTIONS OF SECTION G. 875 



■wheel is interposed between each electric motor and its corresponding driviiif 

 wheel in auch manner that they can all be thrown in and out of gear at the 

 pleasure of the driver. 



The electric motors, which are the most delicate part of the machine, are 

 carried on a platform supported by the springs, and consequently are not subject to 

 the shocks caused by inequalities of the road. 



Another advantage of this type of engine is that it can be constructed of any 

 reasonable size, and maj' therefore be far in excess of the power of the largest 

 steam locomotive, wliich is limited by the size of the boiler. The dead weight 

 also of this engine would be considerably less in proportion to that of the steam 

 locomotive, as the tractive force is obtained by gripping the central rail, and not 

 by gravity. It is especially applicable to lines where the gradients are steep. 



6. Coin-counting Machine at the Royal Mint. 

 By Lieut. W. B. Basset, E.N. 



It was originally the practice to make up the bronze coinage when ready to be 

 sent out from the Mint into parcels of definite value after they had been ' told 

 lip ' by the scale in the manner well known to bankers, without actually counting 

 the number. This plan was, however, found to lead to uncertainty, since it 

 requires considerable accuracy to finish coins of exactly equal weight to each 

 other. 



Although the average weight of bronze coins is correct it might occur that the 

 aggregate error in a parcel of 1,000 or 1,200 coins would amount to the weight of 

 several pence. 



In order to avoid this discrepancy it became necessary to count the bronze 

 coins instead of weighing them, the usual quantity contained in one bag being 51. 

 worth, or 1,200 pence. 



The counting has for many years been effected mechanically in two ways. 

 In the first method a man held beibre him a flat tray, of about 100 square inches 

 area, lined with a brass plate, this plate having in it a number of circular recesses, 

 each culpable of receiving and holding a coin. In this tray he placed a quantity 

 of coins, and after shaking them level he threw out the upper layer, leaving a 

 certain number of coins in the recesses of the plate. After filling up any recesses- 

 that might be vacant he inverted the tray, allowing the coins, which would be of 

 a known number, to fall out. The operation was then repeated. This method is 

 rather slow and laborious, although very certain, and a step in advance was taken 

 by the construction of a machine having a thin steel plate, rotated by hand, with 

 holes in it disposed in two circles. A tube or hopper is fixed over each circle of 

 holes, with its mouth just clear of the rotating plate, and these tubes are tilled up 

 with coins lying flat on each other, thus feeding themselves into the holes in the 

 plate as it revolves, and dropping out before completing a revolution. The machine 

 is stopped by an automatic catch as soon as the plate has revolved a certain 

 number of times. These machines, which were constructed by Messrs. James 

 Watt & Co., of Birmingham, are still in use, and have worked well for a number 

 of years ; but a certain amount of trouble and manual labour are required to keep 

 up the supply of coins to the feeding tubes, and the machine which is the subject 

 of this paper has been designed to work with less labour on the part of the 

 attendants than was formerly the case, as well as ensure a greater rapidity. 



This machine has now (July 1892) been working at the Eoyal Mint for six 

 months with satisfactory results. It is capable of counting pence at the rate of 

 tifty per second, or 3,000 per minute, or four bags, each worth 6/., in about one 

 and a half minute, which corresponds to one ton of copper coinage in forty-five 

 minutes. 



The machine consists of four separate counters, each of which can be worked 

 independently of the other three. They are placed in pairs, two on the right hand 

 and two on the left, upon a platform or stage, so as to allow head room for an 

 attendant below, thus economising floor space. The coins are brought in a quantity 



