2l8 



WITH SCOTT : THE SILVER LINING 



and held together by brass nails. It also formed a camera 

 obscura for meteorological purposes. A lens in the roof pro- 

 jects the clouds on to a sheet of squared paper. This sheet is 

 rotated until the clouds appear to move along a set of lines, 

 and by comparing this with a compass the direction of their 

 movement is obtained accurately and quickly. 



That evening I helped to festoon the hut with telephone 

 wires. While so engaged I saw my first aurora, and it did 

 not impress me. " Like a huge broad cirrus cloud right across 

 the sky from W.N.W. to E.S.E. No colour or movement, 

 and it only lasted five minutes." 



Wright and I assisted Simpson to send up a ballon sonde. 

 This seemed a complicated business at first. We had to carry 



9 



0<rv^SO"->\'£ O^C 



out a queer theodolite with the 

 eyepiece inserted at right angles 

 to the telescope at the side ; and 

 a large tank for generating the 

 hydrogen ; and the inner tube 

 of a bicycle tyre — and various 

 reels of silk, etc., etc. ; not to 

 mention a small tissue-like de- 

 flated balloon of red gutta-percha. 

 The tank was filled from a 

 convenient tide-crack in the 

 sea-ice, and then Charles filled 

 the cycle-tube with calcium 

 hydride. This compound is 

 analogous to carbide, but gives 

 off hydrogen instead of acetylene. 

 He attached it to the top of the generator, and squeezed it to 

 push the lumps of hydride into the water. The balloon was 

 attached to an outlet pipe, and gradually lost its dejected 

 appearance and became a red sphere of some two feet diameter. 

 In about ten minutes the balloon was inflated. This was 

 merely a test, and after tying a piece of silver paper on the 

 balloon it was set free and rose rapidly. With the theodolite 

 the vertical and horizontal angles could be plotted, and thus 

 the path of the balloon charted approximately. 



The sun was setting (at 3 p.m.) while we were doing this, 

 and gave a yellow glow to the steam-cloud on Erebus, which 

 was drifting to the south-east. When the balloon was about 



sketch showing the balloon 

 unwinding the black silk 

 threads from the two conical 

 reels. 



