Of a Country on the Climate. 



215 



outj each of tliem being an inlet for the waters falling on the 

 surface. A retentive bed of clay may stop the descent of 

 the water, at a depth of ten feet, as, for example, beneath 

 the alluvium. When this basin is full, and overflows, it is 

 received in a lower basin, the retentive stratum of which 

 maybe at a depth of 100 feet, and thus downwards. This 

 is not an ideal section, at variance with truth, but illustrates 

 what is met with in practice.* Let us not, however, view 

 this as an isolated case. Let us assume that the older strati- 

 fied rocks and granite of this country were covered with 

 j)aleozoic Coal and Secondary strata throughout large areas ; 

 can we estimate too extravagantly the changes of climate, of 

 soil, of river currents, which would be the result ? Instead 

 of the rains being collected in shallow basins, exposed to the 

 rays of a subtropical sun, or absorbed by thin beds of graA^el, 

 which can retain only small quantities of water^we should 

 have vast reservoirs at various depths, the waters of which, 

 continually reappearing as springs, would render the climate 

 moist and cool ; and the rivers, fed from inexhaustible sources, 

 would suffer little change, even during the heats of summer. 

 The evaporation from the streams would be scarcely more 

 than at present ; for though the volume of water might be 

 largely increased, it is an ascertained fact, that the depth of 

 a river increases in far greater proportion than the width, 

 thus presenting a proportionably smaller area exposed to 

 atmospheric influences. 



I may here cite a few instances, proving in some degree 

 the extent of subterranean lakes. Mr. Mulot was engaged 

 ten years in conducting the boring through the beds of the 

 Paris basin, and he penetrated to a depth of 1,800 

 feet. This magnificent enterprise was most successful. 

 The water rises to a height of ninety-eight feet above 

 . the surface, and discharges at the rate of 600 gallons per 

 minute. 



At Southampton, at Chiswick, in various parts of England 

 and France, the chalk has been reached by boring or sinking, 

 and the supply of water thus obtained, though enormous, 

 must bear no proportion to that flowing from such reservoirs 

 to the sea. In Africa, the natives are said to find water at 

 great depths in the deserts. In nearly all other countries 



* At tlie Monkwearmouth Colliery, in the County of Durham, a spring was 

 struck at a depth of 300 feet, after passing through the magnesian limestone, 

 and the lower new red sandstone. It poured in water at the rate of 3,000 

 gallons per minute. At a depth of 1,000 feet a fresh spring was found, also 

 very considerahle, which obliged the proprietors to erect additional machinery, 

 to clear the workings of water. Instances of this kind might be multiplied. 



