178 
FIFTH REPORT — 1835 . 
function of the height would be greater and the coefficient less, 
and that both of these would be subject to less variation in 
lower latitudes, and the contrary. It is also probable that the 
decrease in the quantity of rain, as w r e ascend above the surface, 
will be least in the warm regions of the globe and greatest in the 
cold zones. There is less difference at Paris than at York. 
Fourthly. It is probable that in countries uniformly moist, 
or of uniform temperature, the results would be materially dif¬ 
ferent from those obtained in a climate so changeable as that of 
the British Islands. 
Fifthly. It would follow from the formula that the differences 
in the values of § h and p in different years depend very much 
upon the season of the year when the rain fell in greatest quan¬ 
tity. Thus, <p h was greatest in 1832-3, and nearly twice as 
much rain fell in the warm as in the cold months; $ h was 
least in 1833-4, and in that year, on the contrary, the larger 
proportion of rain fell in cold months. 
Sixthly. It is probable that there will be found real differences 
between the results obtained for daily and nightly periods. 
I may now propose a plan of experiments sufficiently within 
the command of ordinary observers, and likely, if executed con¬ 
temporaneously at three or more selected points, to furnish a 
mass of good evidence towards the mathematical investigations 
which the subject seems to deserve. These should include uni¬ 
form daily measures of temperature of the air and moist sur¬ 
faces, amount of evaporation, direction, and mean velocity or 
amount of wind, and fall of rain at three or four stations, the 
height of the two or three upper ones being known to feet and 
inches above the lower one, which should be on the ground. 
The height of this above the level of the sea should be ascer¬ 
tained. The following is a plan of the register proposed, which 
includes some occasional observations. The instruments must 
all be furnished by the Association. 
[Place], N. Lat. [ ], TV. Long. [ ], above Sea in Feet 
], Mean Temp, of the Year [ ]. 
Date. 
Barometer 
and 
Thermom. 
Wind. 
Ground—above mean 
level of the sea, feet 
[ 
Middle—above ground, 
feet [ j. 
Upper—above ground, 
feet [ J. 
Dir. 
Vel. 
t. 
t r 
Evapo¬ 
ration. 
Rain. 
t. 
tj. 
Evapo¬ 
ration. 
Rain. 
t. 
tb 
Evapo¬ 
ration. 
Rain. 
9 A.M. 
9 P.M. 
29-865 
29-873 
60 
61 
E. 
E. 
15 
10 
62 
63 
I O Cn 
| 50 00 
1-132 
1731 
61 
62 
57 
59 
1-000 ! 
1-500 ! 
60 
61 
56 
59 
•800 
1-200 
