176 
FIFTH REPORT -1835. 
Having thus reduced both the function of height and the 
coefficient to a dependence on temperature, we are enabled to 
institute a very severe comparison of the formula with experi¬ 
ment. 
Observed. 
Calculated by 
- V 
<Ph ^ h U0 
Calculated with 
#2*8 
p/= 4 —- — *200. 
V 2-8 
Values of 
d. 
d'. 
and p - 
,2-8 
-hi _ 
V 2-8 
<ph, 
<ph„ 
P> 
Pr 
Annual. 
40*44 
20-27 
40*48 
20-18 
40-16 
20-02 
10-57 
5* 27 
3-83 
3*80 
3 summer months 
55-65 
14-17 
38-10 
15-90 
35-85 
15-00 
19-07 
7-98 
1-99 
1-88 
5 warm months . 
35-18 
15-50 
38-00 
16-40 
36-14 
15-61 
17-13 
7-40 
2-22 
2-11 
7 warm months . 
35-58 
16-60 
37-40 
17-36 
36-96 
17-16 
14-49 
6-73 
2-58 
2-550 
7 cold months . . 
46-42 
26-18 
44-34 
24-65 
44-8 
24-96 
7*26 
4-04 
6-10 
6-179 
5 coldest months 
47-40 
26-58 
45-70 
25-90 
46-37 
26-55 
6-74 
5*83 
6-78 
6-88 
3 winter months. 
50-06 
29-74 
49-38 
30-30 
50-37 
29-89 
5-85 
3-46 
8-47 
8-64 
It may be proper to offer some remarks on the probable con¬ 
sequences to meteorology of prosecuting this subject both ma¬ 
thematically and experimentally, and to indicate a form of ex¬ 
periment which may be advantageously followed in all cases. 
Admitting that the three years’ results above discussed are a fair 
average for the climate of York, and adopting the formula as ex¬ 
pressing at least the nature of the proximate influential causes, 
we shall find its interpretation full of curious interest. 
First, it must follow that, upon the average, rain (commencing 
at what Sir John Herschel calls the vapour plane) originates at a 
greater elevation in the atmosphere in the summer than in the 
winter. This is in conformity with Crossthwaite’s Table of 
Clouds, given in Dr. Dalton’s Meteorological Essays , where in 
the five warmer months, May, June, July, August, and Septem¬ 
ber, 219 clouds in a month are noticed above 1050 yards in 
height, but in November, December, January, February, and 
March only 126. 
The same inference results from considering the rain as ori¬ 
ginating either at a height corresponding to a certain reduced 
temperature, or at the point in the air where the dew-point 
= the m.t. of the period. In this latter case, using Mr. Daniell’s 
numbers for the climate of London, the vapour plane, or origin 
of rain, will be 
In January.. 900 feet high. 
In July . 3270 ,, 
For the whole year ... 1650 „ 
The view previously advanced,' that the rain-drops augment 
