266 



Note to Mr. Vincent Tregear's Process of taking casts of Coins. 



vide No. 1 10. 



I must not omit to observe, that the above process cannot be applied 

 to all coins indiscriminately. Copper and brass coins are sometimes so 

 much oxidated as to be unable to bear any pressure, and therefore would 

 be broken if put in the press ; those of gold or silver are seldom endanger- 

 ed ; but still the operator must use a little discretion. Care must also be 

 taken not to continue the pressure further than is required for the per- 

 fect copy of the coin, as after the latter has sunk to the full depth of 

 the relief, a lateral extension takes place, which will injure it, as I have 

 found by experience. 



