ON THE FINENESS OF THE ONE YEN SILVER COIN. 



303 



New Method. A careful study of the distribution of silver in 

 the coin has induced us to choose for our assay of the Silver Yen, 

 three circular punching* of equal weight taken from the angles of an 

 equilateral triangle, which may be supposed to he described on the 

 coin, the distance of the centre of each punching from the circum- 

 ierenceofthe coin being made equal to one-seventh of the diameter. 

 Portions of metal taken from any set of such positions when put 

 together, give almost exactly the average fineness of the entire coin, 

 of which therefore they are the true representative sample. 



Thus in Figure 8, let c be centre of the eoio, ml be its diameter 

 and the middle line of the bar. Let cc', diameter of the inner 

 circle, be equal to *- ml, and let equilateral triangles be described 

 in this circle as shown. 



Fig. 8. 



