1904.] Constant-Standard Silver Trial-Plates. 



"Weighing 7*870 kilogrammes. 



127 



75 cm. bj 90 cm. and i mm. in thickness. 



Another cast simply into a cold mould, and rolled to a thickness of 

 1 mm., gave — 



c 



325-2 



O 



925-2 



O 



925-2 



O 



925-2 







925-2 



o 



925-2 



» o 

 925-2 



O 

 925-2 



O 



925-2 





 925-2 



o 



325-2 







o 



925-2 



O 



925-2 







925-2 



o 

 925-2 



O 

 925-2 



o 



925-2 







325-2 







925-2 



O 

 925-2 



O 



925-2 



°925-2 







9252 



This only weighed 3*640 kilogrammes, is without any wave of 

 variation, and is absolutely constant. 



The hitherto accepted theory "that the molecular rearrangement is 

 comparatively slight if the mass of metal is slowly and uniformly 

 solidified "* is contradicted by the results I have obtained; and the 

 results all bear out the fact that there is little or no difficulty in 

 obtaining an 8 or 10-kilogramme plate of constant-standard silver, or 

 even more if necessary. 



* Fourth Annual Eeport, Deputy Master of Mint, 1873, p. 46. 



