THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



271 



Grouping the results by seasons, the percentage of possible sunshine is 20 in Spring, 

 13 in Summer, 10 in Autumn, and 1 1 in Winter. 



The diurnal variation of bright sunshine is shown in the following talde : — 



Bright Sunshine for Hour Ending 



* For period February 1st to 21st. 



Hence in Spring the sunniest hour is that ending with noon, and the sunniest period 

 the three hours ending with noon. In Summer the sunniest hour is that ending with 

 1 P.M., and the afternoons have much more sunshine than the forenoons, doubtless due 

 to the prevalence of fog and mist in the early part of the day which disappears as the 

 temperature rises. 



Maximum in Sun. 

 A solar maximum registering thermometer (black bulb in vacuo) was exposed after 

 12th May 1903 at the Omond House station, but was not read regularly until the begin- 

 ning of September. The values given in the following table are accordingly for the year 

 ending August 1904. I am indebted to Mr W. G. Davis, Director of the Argentine 

 Meteorological Office, for permission to utilise the data for the six months, March to 

 August 1904. The instrument on several days could not be read owing to the values 

 falling below the scale, so that in computing the excess over the shade temperature only 

 those days have been taken on which the solar maximum was recorded. 



Maximum Eeadings ix Sun. 



1903. 



September 

 October . 

 November 

 December 



VOL. II. 



Mean Solar 

 Maximum. 



84-4 

 108-2 

 126-6 

 124-6 



Excess over 



Sliade 

 Ma.ximuui. 



64-4 

 86-0 

 94-2 

 90-6 



Days' 

 Observations. 



22 

 24 

 29 

 31 



Absolute 

 Maximum. 



lin-0 

 139-0 

 158-9 

 159-5 



Date. 



5 

 29 

 11 

 23 



37 



