110 
every case the difference of rainfall between the two gauges 
is as the difference of the moisture of the atmosphere ; but 
if these differences be compared with the ratios of the 
amount of wind on each day of rainfall, it will be found 
that there is little or no comparison. For example, though 
in November there was above the average amount of wind, 
and an apparent consequent large difference between the 
rainfall in the two gauges, yet in June and July, when the 
amount of wind was below the average, a similar difference 
of rainfall happened ; and again, though the amount of wind 
in May was about equal to that in October, yet there is a 
great difference in the difference of rainfall. 
The wind may play some part in causing this difference 
of rainfall between the two heights, but I think it is only 
a secondary cause, that is, when it brings with its force a 
large supply of relatively moist air. But when it brings a 
supply of dry air on a rainy day, though there be a strong 
current of wind blowing, the difference of rainfall will be 
very small, as illustrated in the amount of rainfall and wind 
movement in May of the past year. 
1877. 
Eatios of such 
Eainfall 
for 1877. 
Eatios of such 
Eainfall for 
Average of 
10 years from 
1SG7 to 1877. 
Mean Humidity 
of the 
Atmosphere for 
10 years from 
1867 to 1877. 
January 
•764 
•718 
•872 
February 
•818 
•773 
•857 
March 
•872 
•795 
•833 
April 
•826 
•837 
•775 
May 
•851 
•893 
•753 
June 
•796 
•861 
•743 
July 
•793 
•888 
•763 
August 
•865 
•850 
•793 
September 
•886 
•864 
•779 
October 
•798 
•837 
•836 
November 
•765 
•793 
•854 
1 December 
•731 
•793 
•873 
: 
Annual Eatios 
•808 
•825 
•810 
