OX THE FINENESS OF THE ONE YEN SILYEB COIN. 



307 



Table VI. 



Showing Assays of Mass compared with 

 Average of individual Assays. 



A small screw press worked by hand is used by us for cutting 

 out the small circles from the coin (Fig. 9.), one circle being punched 

 out nt n time. A steel punch of the required diameter is attached to 

 the screw. The ruin is introduced by means of a brass sliding guide. 

 The constant position which the guide is caused to take brings the 

 coin to the exact relative position with regard to the punch. The 

 latter descends by the action of the screw and cuts oui n circular piece 

 from the required position. The coin is then turned round Through 

 an arc of 120° in the guide by bringing the hole made by the first" 

 puuching opposite n mark on the guide. A second action of the screw 

 punches out another circle. The coin is turned round another 120° 

 and the third circle is cut out. The process is simple and may be 

 performed in less than half a minute The somewhat large size of 

 the cutter, or punch, and the very simplicity of the apparatus make 

 any accidents extremely rare. 



In this apparatus, the punch strikes out circular pi if almost 



exactly the same weight. In default of the punch, we recommend the 



