I 



1915. No. 5. ROALD AML->D5E-\'5 ANTARCTIC expedition: METEOROLOGY. 3 



and have answered exceedingly well. They have been tested at the 

 Meteorological Institute in Christiania by means of observations with Ass- 

 mann's aspiration Psychrometer, and the Tables of correction constructed 

 from the comparisons. 



It is to be assumed that the corrected values give a fairly accurate 

 representation of the Relative Humidity. On the lo*^ October, whoi the 

 temperature changed from ^ 46° to — 52°, there is a sudden change in 

 the reading of the hygrometer, but the corrected reading does not show 

 any remarkable change of humidity. From the i^ April to the 13*^ October 

 No. 14 was employed, and from that day to the 29*** January No. 12. 



The hvgrometers were placed in a louvre-boarded screen together 

 with a thermograph and a thermometer. The screen was a broad English 

 hut standing on four posts, |yj 



erected at a distance of 

 14 m. to the south-east of the 

 dwelling-house. The height 

 of the instruments from the 

 surface of the snow was 

 about two metres. 



The tension of vapour 

 has been computed from 

 the relative humidity and 

 the temperature of the air. 



-Z 



/If- 



D---- 



C 



Fig. a. 



a Thermometer Hut, b Wind Vane. 



Aaeaionieter. 



4. Wind. 



The direction was ob- 

 ser\ed with a vane at the 

 top of a pole, 6 m. east of 



the thermometer-screen or 20 m. ESE of the house. The direction is true. 

 The velocity was observed with Mohn's hand anemometer in metres per 

 second. Description of this instrument is to be found in the »Norwegian 

 North Adantic Exp)edition« 1876 — 1878. Second Volume. Meteorology, 

 pp. 6 — 10, and in the »Quarterly Journal of the Roy. Meteorological So- 

 ciety (London) for January, 1878, pp. 37 — 39- The place where the ane- 

 mometer was whirled was 9 m. E by S from the thermometer-screen, and 

 some 3 metres from the vane. The friction coefficient of the anemometer 

 was I m. This has been added to the numbers noted bj' the observer. 

 Direction noted without velocity signifies a wind of which the direction 

 could be observed but which had a velocity of less than i m. per second. 



