32 
ME. J. E. H. G-OKDON ON THE DETEEMINATION OE 
Set. 
Dates of vibration experiments 
at Pixholme. 
Mean value of 
H at Kew 
(Corrected square of 
vibration time at Pix- 
holme) X (Mean value 
of H at Kew) 
at these dates. 
1. 
1876. 
April 23, 6.30 i*.m 
0-179368 
2-44362 
C) 
April 25, 10 a.m 
0-178935 
2-43688* 
3. 
April 28, 10.30 to 10.50 a.m. 
0-179024 
2-44395 
4. 
„ „ 2.2 to 2.15 p.m. ... 
0-179190 
2-44281 
5. 
„ „ 5.45 to 6 p.m 
0-179245 
2-44339 
Mean -. 2-44344 
This gives 
H at Pixholme =(*993366) H at Kew. 
But at the dates of the optical experiments' H had, at Kew, the values given in the 
second column of the following Table, and therefore at Pixholme those in the third. 
Set, 
Dates of optical experiments at 
Pixholme, 1876. 
Mean values of H 
at Kew 
Mean values of H 
at Pixholme 
at these dates. 
1. 
Feb. 25, 11 to 11.30 p.m 
0-179H7 
0 177929 
2 , 
Feb. 25, 11.30 p.m. to Midnight 
0-179241 
0-178051 
3. 
Feb. 25, Midnight, to Feb. 26, 0.30 a.m. ... 
0-179244 
0-178055 
Dividing the three values of — given on page 20 by these numbers respectively, we 
have, for the three quantities which ought to be identical, 
||=(1) 50118-4 
(2) 49767*0 
(3) 49538-7 
Mean . . . 49808-0 
Extreme difference from the mean 0*6 per cent. 
We have, finally, then, if u be the rotation in bisulphide of carbon of the plane of 
polarization of the ray whose wave-length is 
(5-349)10- 5 
Eejected. 
