HUMIDITY OF THE AIR. 



159 



Here it appears very clearly that the greatest disproportion is 

 in the coldest season, and the least in the warmest months. If we 

 take the differences between the numbers which express the rain 

 on the Minster and Museum, and 100, we have the column 

 marked d+d' in the table below. In the column next to this, 

 the mean temperature of the seasons is placed ; that of the whole 

 year being 48*2. Thus it clearly appears that as the mean tem- 

 perature rises, the difference between the high and low gauges 

 diminishes. The third column is formed by multiplying to- 

 gether the numbers in columns I. and II. The near equality of 

 these numbers shows the dependence of this curious phenome- 

 non on temperature to be very close and essential. The mathe- 

 matical computations to which the subject leads will be found 

 in the original memoirs (Brit. Assoc. Reports for 1833, 34, 35). 



It is only necessary to say here, that the theory to which the 

 whole investigation appears to conduct is very simple. " The 

 difference in the quantity of rain, at different heights above the 

 surface of the neighbouring ground, is caused by the continual 

 augmentation of each drop of rain from the commencement to 

 the end of its descent. As it traverses successively the humid 



