Dissertations on Coins, Weights, Uc. 19

that it requires better Eyes than mine to make them out.

By the Inscription 8. C. O. the Coin was struck by the Au-thority of the Senate, which perhaps made the Mint-mastersmore careful, than when they wrought by the Authority ofthe Consuls, Prætors, Ædiles, &fc. as they did sometimes.

Vide Rink, p. 123.

g r -'

The Weight of this Coin, in Air, is - - - - 61.625

in Water, - - - 55.875

Difference - - - - 5.750

The Way to find the specific Gravity is this : As the Differ-ence between the Weight in Air and Water is to the Weight

, O O

in Air, so is i.ooo to the Number sought. Thus as5.750 : 61.625 ' - 1.000 : 10.717, &fc. Which lastNumber 10.717, shews the specific Gravity. Since the spe-cific Gravity of our Standard Silver, is generally set at1 0.535, it seems at first Sight as if this Coin considerablyexceeded our Standard. Yet if we consider the specific Gra-vity of King Williams Half-crown, mentioned before, at10.75, ^ w iA appear that this Denarius is exceeded by itbut a Trifle. Nay, since this Denarius has a very bold Re-lief, it must have been compress’d and condens’d so much inthe Coinage, that it is a Question whether the Metal of it be-fore Stamping, was any thing heavier than our Standard.

This Coin is specifically heavier than any of those thatfollow ; consequently it is of finer Silver : For an Alloy ofany base Metal will make Silver lighter, Lead only excepted:

But we have Savotms Word for it, that in his Eflays on an-tient Coins, he never met, with a Grain of Lead in any ofthem before the Time of Septimius Sever us, when a Mix-ture of Brass and Lead was made use of to allay the Silver.

Vide Joubert. p. 22.

D 2

This