678 :me. aiey’s accouxt op the coxstehctiox of 
Section VII. — Comparisons of numerous bars from 1851 to 1855; suspicion of change in 
Bronze 28; removal of the suspicion; close of the operations for defining the Yard 
by line-measure. 
I have interrupted the chronological order, for the sake of bringing together in the 
last Section the observations of fundamental character, and in the present Section the 
mere determinations of the length of numerous bars. 
In a former Section I gave the differences found by Mr. Sheepshank.s between 
Bronze 12 and the folloAving bars (among others) — 
Bronze 6 
8 
18 
21 
22 
23 
24 
25 
26 
27 
29 
and also Bronze 28 
These bars were subsequently compared with Bronze 28, and they therefore afforded 
very good means of comparing the two fundamental bars Bronze 12 and Bronze 28. 
Their excesses above Bronze 28 were as follows: — 
d. 
Bronze 6 +2 '90 
8 +1-73 
18 -3-32 
21 +2-22 
22 +2-62 
23 +3-12 
d. 
Bronze 24 -f 3T2 '' 
25 4-4'77 
26 +4-47 
27 +1-84 ^ 
29 +3-71 
and direct comparisons had 
given for Bronze 12+l«^-55. 
Combining these differences with the differences of the same bai's from Bronze 12. 
inferring from each the value of Bronze 12 with respect to Bronze 28, and taking the 
mean of all, with fivefold weight for the direct comparison, 
Bronze 12=:Bronze 284-l‘^'84. 
This value was used for connecting the inferred lengths (from comparison with Bronze 
12) with the inferred lengths (from comparison Avith Bronze 28): then, in all cases Avliere 
both bases had been used, a general mean w'as taken. 
Thus by comparison, sometimes with one base, sometimes Avith tAvo, the folloAving 
differences from Bronze 28 Avere determined. For conAenience of reference. I haAC 
included in the same Table the differences determined in the last Section. 
