Contrlltition towards the assayi/ig of Coins. 263 



No. 13. On the one side ahead of Vespasian : on the 

 reverse a soldier sitting. It weighed 360 grains, and con- 

 teined 



Copper - - - 293 grs. 



Ziac . - - 59 



Lead _ _ - 4 



Tin - - - 3 



Iron r- - - 1 



360 



No. 14. On one side the head of Trajan : on the reverse 

 a sitting figure, which seemed to be a Vesta. It weighed 

 382 grains, and was composed of 



Copper - - - 326 grs. 

 Zinc - - - 53 

 Tin ^ - -. 3 



382 



No. 15. Another coin with the head of Trajan: and a 

 similar figure on the reverse, It weighed 365 grains, and 

 giive 



Copper - - - 294 grs. 

 Zinc - - - 60 



Tin - - - H 



365 



It appears from these results that the Greeks, for their 

 early coins, employed in general a mixture of copper, zinc, 

 and lead. On the other hand, that the Roman coins are 

 of two kinds, one of which consists only of copper, and 

 the other of a mixture of copper and zinc. 



The custom of mixing copper with zinc may be traced 

 back to the remotest periods. It is well known that the 

 oldest nations employed copper in general for their utensils, 

 and even for their sharp cutting instruments. But as cop- 

 per, and especially when cast, is not of itself sufficiently 

 hard for that purpose, it may be readily conjectured that 

 experiments were made at a very early period to commu- 

 nicate to it a greater degree of dcnseness and hardness by a 

 mixture with other metals, none of which, except tin 

 alone, wore likely to answer the proposed end.^ Such mix- 

 tures of copper' and tin were called by the Greeks yyrov, 

 and by the Romans as caldurlum, as at present, accord- 

 \\ 4 >nS 



