estimated In parts of the English standard. 107 
brass were parallel, and consequently that their rectangular 
ends were perfectly in contact. 
The distance between the lines on D and d , was now taken 
by the microscopes, and transferred to the scale in the manner 
before described ; and when a sufficient number of compari- 
sons had thus been made, the pieces D and d, were exchanged 
for those marked C and c, and the observations repeated with 
every precaution to ensure an accurate result, especially with 
respect to temperature. 
The under surface of the metre was then placed upper» 
most, and the apparatus being arranged as before, the same 
process was pursued as that which has just been described. 
The results are contained in the following tables. 
Comparison of the metre d bouts. 
The pieces D and d, applied. Distance from D to d , 456,7 
divisions. The word Metre above. 
Tempe- 
rature. 
Reading of 
the microm. 
at 39,4 of 
the scale. 
Reading of 
the microm. 
at the brass 
pieces. 
Differ- 
ence. 
Divisions to 
be deducted 
from 39,4 
inches. 
Length of the 
Mitre. 
Corr. for 
temperature 
in decimals 
of an inch. 
Length of the 
Metre, the metre 
being at 32 and 
the scale at 62®. 
S9>7 
9*5 
9‘*5 
82,0 
538,7 
39*37 6 94 
,00610 
39.3708 3 
54,8 
38,0 
97* 2 
59* 2 
515*9 
. 39*37792 
,00713 
39*37079 
55»° 
39*° 
98,0 
59*° 
515*7 
39*37793 
,00709 
39*37084 
55** 
36,2 
95*o 
58,8 
515*5 
39*37794 
,00707 
39*37087 
5 5* 2 
36,0 
95,0 
59*° 
5^5*7 
39*37793 
,00705 
39,37088 
Mean 
39*37084 
The pieces C ; and c, applied. Distance from C to c, 500.5 divs. 
The word Metre above. 
5.6 
30,7 
47*5 
16,8 
517*3 
39>37786 
,00696 
39*37090 
55*7 
30,0 
47*3 
1 7»3 
517,8 
39*37784 
,00694 
39,37090 
55*9 
30,2 
47-* 5 
1 7»3 
517*8 
39.37784 
,00690 
39,37094 
56,2 
24,5 
45*0 
20,5 
521,0 
39*37770 
,00684 
39*37086 
56,3 
23,0 
44*7 
21,7 
522,2 
39*37765 
,0068 I 
39*37084 
Mean 
39*37089 
