(811 ) 
~ - 1,386.10— 7 
whence it follows that x:i°35 k.= 272,0.10“ 6 . 
Finally, at — 209°,2 C. a single observation was made. The rise 
was 6.115 cm. in a field of 6600 gauss, which with the correction 
for the sinking in the reservoir gives 
4 - = 1.444.10~ 7 and X63 o. 9K . = 283.4.10-«. 
H 
We shall now give the series of observations made with the 
silver-walled apparatus which we have already described. 
X9o°iK. = 240.6.10-* 
