LXXII 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
troy ounces. In that case the summation of the several columns 
gives ' ^ 
512 ounces = 128 + 39 grains 
whence 
X = 4 ounces — 0‘3047 grain (2) 
and by substituting that value in the equations (1) we obtain the 
corrections to the several weights given in the second column of 
Table I. 
\ 
Table I .—Corrections to the Exchequer Standard Troy Weights of 1588, 
derived from the Weighings made by Messrs. Harris and Chisholm. 
Denomination 
of 
Weight. 
Apparent 
correction 
in 1758. 
Committee’s 
correction 
in 1758. 
Chisholm’s 
correction 
in 1873, 
Loss by 
wear in 115 
years. 
Grains. 
Grams. 
Grains. 
Grains. 
4 ounces divided-- 
— 0-30 
— 0-42 
— 1-69 
— 1-27 
4 ounces __ 
•55 
•67 
0-68 
0-01 
8 ounces ..._ _ 
•86 
0-58 
1 09 
0-51 
16 ounces _ 
•97 
1-42 
3-84 
2‘42 
82 ounces _ - 
— 0-19 
1-08 
3-82 
2-74 
64 ounces . _. 
+ 0-62 
— 1-17 
— 5-04 
3-87 
128 ounces _ - 
+ 12-25 
-f- 8-67 
+ 4-28 
4-39 
256 ounces _ -- 
— 10-50 
— 17-67 
— 53-58 
— 35-91 
Sums 
± 0-00 
— 14-34 
— 65-46 
— 51-12 
From equations (1) and (2) we have 
4 ounces = 4-oz. weight + 0 5547 grain. 
8 ounces = 8-oz. weight + 0'3594 grain, 
whence it follows that the sum of the eight and four ounce weights, 
which constituted the Exchequer standard troy pound, was too light 
by 0'9141 of a grain. As the mean correction obtained from the 
four weights belonging respectively to the Mint and to Mr. Free¬ 
man agrees closely with this result, the true correction to the Ex¬ 
chequer standard must have been very approximately one grain; 
