Loris] THE VARIATION OF WATER VAPOUR LINES 49 
3rd. In each case a storm ensued. It is possible that the water 
vapour area was situated at such a height and in such a direction that 
the sunlight did not traverse it until noon. 
4. It will be seen that the curves representing the intensity and 
the temperature follow the same general course. Thus far the obser- 
vations indicate that the intensity is mainly a function of the tem- 
perature and the humidity, but it is hoped to continue the work for 
some time in order to see how far the accumulation of masses of aque- 
ous vapour in the atmosphere may differ from time to time, during 
corresponding seasons of the year. 

Note: March 6th, 1911, by H. T. B. Owing to ill health Mr. Gillis was 
obliged to abandon this work. The observations gave promise of interesting results, 
and it is hoped others may be induced to follow the variation of the water vapour 
lines by Cook’s method. 
Sec. III. 1910. 4. 
