[ 443 ] 
Metals themfelves, and to the fcveral degrees of 
their mixtures one with another, if experiments in 
all thefe cafes were but made with afufficient degree 
of'accuracy. 
Gold, in the experiments I have made myfelf, I 
-could never find to come up to the weight affigned 
it in fomc of the former tables, and particularly thofe 
I have made upon our own coin, and fome others 
have always remarkably fallen fhort of the weight 
affigned to the Standard in thofe fame tables. I 
have inferted that trial in which I found Guineas to 
come out beft j and 1 may venture to affirm, that 
that experiment, in particular, was made with as much, 
accuracy as my inftrument was capable of, the Pieces 
were all walked in foap and water, cleaned with a 
brufh, and the air-bubbles well freed and the like. 
That experiment is belides abundantly confirmed fince, 
by the exadt trials lately made by Mr. Graham and Mr. 
Ellicot , which were performed with thegreateft care ; 
and the fine Gold aifo mentioned by the laft was 
cholen and prepared with the greateft curiofity. 
It may be oblerved, that the gold medals of Q. 
Eliz and (T_ Mary, quoted by J.C. were, with- 
out doubt, the large Sovereigns of thofe Queens, 
which were of the old Standard of England , or of 
gold appointed to be 23 carats, 3 grains and a half 
fine: That the Mentz Ducat, mentioned by the 
fame, if it was one of thofe ad Legem Imperil , 
which are always in their own mints affirmed to be 
fine, come out confiderably too light : and that the 
gold coin of the Commonwealth, and the piftoles of 
France , were like our prefent gold money of the 
goodnefs of 22 carats. 
Mercury 
