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ascents found the humidity of the air “to increase till reaching 
the first stratum of clouds, afterwards to vary irregularly.”* 
Mr. Glaisher likewise, in working out the results of several of his 
balloon ascents, found “that the temperature of the dew-point 
decreased, on leaving the earth, less rapidly than the temperature 
of the air ; so that the difference between the two temperatures 
became less and less, till the vapour-plane was reached, when they 
were usually together.” 
Another notable circumstance in the results is the larger 
quantity of rain that fell at Ensleigh than in the Institution 
Gardens, during the above thirty-three months. This circumstance 
was alluded to above.t The whole excess is about an inch anda 
half ; the excess being most remarkable in the year 1866, in which 
it amounted to more than five inches, showing itself in every 
month of that particular year, except June and September. This 
difference is not easily accounted for, the elevation of Ensleigh 
being so very much greater than the low parts of the town, and 
the quantity of rain generally diminishing with the altitude. This 
rule, however, which applies to different elevations above a level 
plain, does not, as before stated, necessarily hold good in the case 
of differences of height, due to hills and valleys. At the same 
time it is observable, with reference to the present instance, that 
the mean rain-fall at Swainswick, as given above from the 
measurements of the late Mr. Lockey, is under 26 inches; the 
height above the sea being about 400 feet, and the distance from 
Ensleigh, in a direct line, being very inconsiderable. The fall at 
the two respective places during the particular years of 1865-68 
cannot be ascertained, as Mr. Lockey’s register terminates previous 
to that period. On the whole, I am inclined to consider the 
anomaly as due in part to elevation, in connection with the 
configuration of the surrounding country ; in part also to the rain 
measurements at the Institution being under mark, from the 
* Phil. Trans., 1853, p. 311. + Proceed. of Brit. Meterol. Soc., vol. 1, 
p. 259. f p. 270. 
