ON RAIN, EVAPORATION, &C. 173 



but after that time it yielded a quantity after moft rains. An- 

 other veflel of twice the depth, or 16 inches, gave a refult 

 much like that of eight inches. Farther, M. de la Hire found, 

 that when herbs were planted in the foil of the laft mentioned 

 veflel, and grown up, no rain penetrated through the foil, but 

 inftead thereof it was not fufficient to fuftain the vegetation ; 

 for the plants would require to be fprinkled occafionally, or 

 clfe they began to droop and wither. 



With refpedt to the firft mentioned fact, we need not wonder Remarks. Paris 

 that no water penetrated through eight feet of earth at Paris, j^™ 1 ]^*^ 

 where the annuul rain is but 20 inches, when only eight or ra i n} 

 nine inches. penetrated through three feet of earth here, where 

 the rain is 33 or 34 inches annually. But it does not follow 

 that rain may not defcend down declivities of the ground into but the higher 

 vallies or lower parts, at Paris as well as here, and being ac- ^"fhe^may 

 cumulated may penetrate into the earth to a considerable depth, afford waters, 

 efpecially if it meet with channels or chafms of any kind, or &c * 

 declining ftrata of earth that are impenetrable by water. Paris, 

 I believe, however, is not very liberally fupplied with fprings, 

 as might be expe&ed. As to the experiment upon vegetation, 

 it only proves that the rain in fpring and fummer is fometimes 

 not fufficient to fupport vegetable life, a fact which may rea- 

 dily be granted ; but then in his experiment the plants were 

 precluded from a fupply of moifture from the earth beneath 

 the velfel, which is a referve of the utmoft confequence in dry 

 feafons. 



This circumftance of water afcending again in the earth, Water after 

 on whatever principle it is effected, cannot be denied. — There taking into the 

 were 4j inches of rain here in July laft, none of which palled acrain. 3 

 through the earth in the evaporating vefTel » this earth, how- 

 ever, at the end of the month, was far from that degree of 

 drynefs which is unfit for the fupport of vegetation. — During 

 the firft four days of Auguft there fell about three inches of 

 rain, and only £ an inch penetrated through the earth in the 

 evaporating veflel. Confequently three feet in dej/h of eartli 

 that was moderately moift imbibed nearly three inches of rain 

 before it was faturated ; whence we may conclude that three 

 inches nearly had afcended and been evaporated. This evi- 

 dently (hews, that earth is capable of holding a very great 

 proportion of water, that in fummer the water afcends to fup- 

 ply 





