458 
SCOTT'S LAST EXPEDITION 
were made in a small cave dug into an ice drift, but did 
not prove at all satisfactory, partly owing to the frost- 
fogging of the lenses and mirrors during the course of the 
observations and partly owing to the intense cold. There 
being more space in the hut during the second winter, 
a second series of observations was undertaken inside, 
a huge kenyte boulder being imported to serve as a solid 
base for the instrument. By cutting a hole through the 
floor of the hut and freezing the boulder to the frozen 
ground underneath, a very solid and rigid stand was 
formed. This second series was carried out in the dark 
room (by courtesy of Debenham), and the coincidences 
observed by telescope through a small window in the 
wall in order to reduce the temperature variation of the 
pendulums. The observations, though not equal to 
those obtainable in a fixed observatory, are quite con- 
cordant and should give sufficient data to substantiate 
definitely the theoretical formula at present in general 
use. 
