PENDULUM OBSERVATIONS 315 



During the first winter the pendulum observations 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 under- 

 taken 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 concordant 

 and should give sufficient data to substantiate definitely the 

 theoretical formula at present in general use. 



