VELOCITY OF WHITE AND OF COLOURED LIGHT. 
265 
December 21, 1880, No. 2 
Wheel. 
Clock. 
Leading. 
Differences. 
At mean reading. 
Leading. 
Alternate 
differences. 
Alternate second 
differences. 
5,790 
8,106 
12,700 
2,316 
2,297 
6,948 
10,403 
5,370 
17,091 
26,755 
38,289 
47,846 
59,302 
21,385 
(21,198) 
21,091 
21,013 
294 
185 
Signal at 8,679 
Signal at 28,958 
«' =-002306 
7=27,726 
4/= 280 
v= 1-0599 
Correction for friction, &c. = — '0008 
v= 1-0591 
A=-,=459-28 
V 
December 21, 1880, No. 3. 
! 
Wheel. 
Clock. 
Leading. 
Differences. 
At mean reading. 
Leading. 
Alternate 
differences. 
Alternate second 
differences. 
8,430 
10,766 
15,400 
2,336 
2,317 
9,598 
13,083 
9,432 
21,958 
32,432 
55,078 
67,330 
77,521 
23,000 
(22,646) 
22,443 
345 
203 
Signal at 12,051 
Signal at 42,348 
F=-002323 
7=43,790 
4/= 282 
v= 1-1323 
Correction for friction, &c. = -f- -0011 
v= 1-1334 
»"=-,=487-89 
V 
From Nos. 2 and 3 
2m 
(»'+»")D b 
r+1 
9 + P 
185,846 
1-00185 
Product =V=186,190 
2 M 
- Correction for second term = + 344. 
MDCCCLXXXII, 
