148 
Philosophical Society a few days since, a statement of rainfall 
in the past year and comparisons with the average fall for 71 
years, I was led to examine the mean monthly values from 
my observations during the last 29 years, in order to ascertain 
how far they would bear out the theory of a maximum value 
in October and minimum in April, and find they agree with 
the theory in every particular, even with the exception in 
September. And moreover I find that the sum 1 of the monthly 
mean values of any two months, six months apart, as January 
and July, February and August, &c., is very nearly the same 
value, being about one-sixth of the yearly average. 
Below are the results, and also Mr. Vernon’s mean 
values : — 
Fall in 
Average of 
Difference from 
1864. 
Days. 
Inches. 
29 Years. 
29 Years Average. 
January 
.... 11 
... 1-479 ... 
2-369 ... 
-0-890 
February . . 
.... 12 
... 3-585 ... 
2-201 ... 
+ 1-384 
March 
17 
... 2-275 ... 
2-133 ... 
+ 0-142 
April 
.... 10 
... 1-260 ... 
2-093 ... 
-0-833 
May 
.... 11 
... 2-833 ... 
2-388 ... 
+ 0-445 
June 
.... 18 
... 3-450 ... 
3-117 ... 
+ 0-333 
July 
.... 9 
... 2-035 ... 
3-294 ... 
-1-259 
August 
.... 13 
... 2-832 ... 
3-595 ... 
-0-763 
September . . 
.... 21 
... 4-130 ... 
3-071 ... 
+ 1-059 
October 
.... 13 
... 2-800 ... 
3-680 ... 
- 0*880 
November .. 
.... 18 
... 3-885 ... 
3-026 ... 
+ 0-859 
December .. 
.... 17 
... 2-860 ... 
2-656 ... 
+ 0-204 
170 
33-424 
33-623 
-0-199 
Monthly means of 1864. 
Ins. Monthly means of, for 71 years. Ins. 
January and July . . . 
5'663 January and July 
... 6-029 
February „ 
August 
5-796 February „ August 5 -9 71 
March „ 
Sep. ... 
5-204 March 
l „ Sep. 
.. 5-545 
April „ 
Oct. ... 
5-773 April 
Oct. 
... 5-856 
May „ 
Nov.... 
5*414 May 
» 
... 5-824 
June „ 
Dec 
5-773 June 
„ Dec. 
... 6-173 
33-623 
35-398 
