Observations on the Purity of Standard Gold, 135 



friction of se/en -eighths of a grain for 2,200 years wearing, 

 and he gratuitously makes the drachma to he 82 whole 

 French grains, which would make 88 and a half of Florence 

 weight. It is best to banish entirely from our calculations 

 all suppositions of friction, because, by admitting this to 

 have been the case, we might draw a variety of vague con- 

 clusions. The weight of 88 grains which we have assigned 

 to the gold drachma is confirmed by a silver one of this 

 very Philip, also preserved in the Florence cabinet: this 

 piece has on its face the head of Hercules without a beard, 

 covered with a lion's skin ; and on the reverse a Jupiter 

 sitting, holding the eagle in his right hand and a spear in 

 his left. It is distinguished from the others by a lyre, and 

 the letter A under the seat. This drachma is also a proof 

 of the exactness of its weight in its half, also in silver, 

 of the same king, which weighs precisely 44 grains : on 

 its face is the head of Jupiter with the diadem ; on the re- 

 verse is a figure on horseback, with the name on the exergue 

 and a mark which is unintelligible. Besides, there are four 

 pieces of four drachmas of Alexander of the same metal, 

 the face and reverse of which are similar: all of these weigh 

 14 pennyweights and 16 grains, and prove completely that 

 the weight of the drachma is 88 grains. These tetra- 

 drachmas are distinguished in the type by the addition of 

 various signs, as we have said with respect to the staterce : 

 one has in front a lamp, and under the seat a moon and a 

 star: another has in front the letter T with a circumflex 

 accent, and under the seat the letter K : another has in 

 front a buckler, and under the seat a serpent : the fourth 

 has in front a crown, and under the seat a monogram com- 

 posed of M. Finally, we have also a real drachma of this 

 king of the precise weight of 88 grains, and which is di- 

 stinguished by a monogram formed by an II, the cross bar 

 of which has a kind of circumflex accent. 



Among the tetradrachmas of Thrace there is one in the 

 Florence collection, and the twelfth of the list, heavier 

 than the rest; it weighs precisely 14 pennyweights and 16 

 grains: here we have a proof of the identity of the weights 

 of the Thracians and Macedonians, as long ago supposed 

 by the learned. 



After the weighing of the Arezzo coin was finished, it 

 was submitted to the cupel and to quartation. The stand- 

 ard was found to be the same with Ruin's examination, i.e. 

 0'9"9> or 23 carats and a half: it contained only half a 

 carat, or 0.021, of silver. 



The art of assaying was known in the earliest times, as 



1 4 attested 



