estimated in parts of the English standard. 
105 
Comparison of the metre a traits . 
Temperature. 
Reading 
of the mi- 
crom. ■ at 
39,4 of 
ttie scale. 
Reading of 
the microm. 
at the metre 
Divisions to 
be deducted 
from 39, 4 in- 
ches. 
Distance in in- 
ches between 
the lines desig- 
nating the me- 
tre. 
Correction 
for tempera- 
ture in deci- 
mals of an 
inch. 
Distance in inches 
retween the lines 
designating the ,, 
metre, the metre 
jeing at 32 ®, and 
the scale at 62 °. 
60,0 
85,0 
644,5 
559*5 
39,37606 
,00604 
39,37002 
60,7 
75*5 
639,0 
563*5 
39 * 375 88 
,00589 
39*36999 
61,7 
69,2 
634,0 
564,8 
39 * 375 8 3 
,00568 
39,370x5 
62,0 
65,0 
630,5 
565,5 
39 * 375 8 o 
,00562 
39*37018 
62,4 
61,0 
629,0 
568,0 
39.37569 
*00554 
39-37015 
62,3 
5 8 *7 
629,5 
570,8 
39*37557 
,00556 
39,37001 
62,2 
58,0 
628,0 
570,0 
39 ’ 3756 o 
,00558 
39,37002 
62,2 
59,0 
625,0 
566,0 
39*37577 
,00558 
39 * 37° 1 9 
62,1 
59 ’° 
625,5 
566,5 
39*37575 
,00560 
39*37015 
58,8 
90,0 
638,0 
54 8 *° 
39*37654 
,00629 
39*37025 
5 9 *° 
83,0 
637,0 
554*0 
39,37629 
,00625 
39*37004 
59 >° 
82,0 
636,0 
554*0 
39*37629 
,00625 
39*37004 
59 > 2 
83,2 
632,0 
548,8 
39*37651 
,00621 
39*37030 
59 * 1 
81,0 
632,0 
55 i*o 
39*37642 
,00623 
39*37019 
Mean 
39*37012 
The distance between the lines designating the 
metre was found by M. Arago to be too 
little by a quantity. — ,00069 of an inch which 
add - 
The distance from zero to 39,4 of Sir G. ShuckA 
burgh’s scale is too short compared with the 1 
mean of its divisions by ,00005 of an inch which f 
subtract® - - J 
Hence the length of the metre in inches of Sir 1 
G. Shuckburgh’s scale is - J 
+,00069 
— ,00005 
39,37076 
The comparison of the metre d bouts, presented considerable 
difficulties, which I conceive it would be of little use to detail, 
as the necessity of comparisons of this kind is of very rare 
occurrence ; I shall therefore proceed to describe the method 
which was at last found successful. 
MDCCCXVIII. 
* See page 54. 
P 
