338 Prof. BischofF on the Temperature of 



The meteoric waters must also have as little power sensibly 

 to raise, as they have to depress, the temperature of springs. It 

 is, therefore, equally inadmissible, that the temperature of springs, 

 in low latitudes, should be sensibly depressed by the coldness of 

 the winter rains, as that, in higher latitudes, it should be raised 

 by the wanntli of the rains in summer. 



Ii) the dislocated rocks of limestone and quader-sand stone, 

 the relations may prove somewhat different. The fissures in these 

 rocks being for the most part of great depth, the meteoric wa- 

 ters flow through their spacious channels in torrents; the influence 

 of the waters on the temperature of the outer crust of the earth, 

 may, therefore, be much more considerable in these rocks. But 

 tile changes efl*ected on the temperature of the earth will still 

 take place, but a short time before those caused in the air. 



In order to form an idea of the extent of the influence of these 

 circumstances, I chose the quader-sandstone and chalk-rocks, on 

 the western declivity of the Teutoburgcr Wald, which are fis- 

 sured to an extraordinary extent, for the theatre of my obser- 

 vations. Many considerable brooks rise out of these rocks, but 

 are for the most part lost in the clefts, and reappear at the foot 

 of the chain. I measured the waters of the Lippe, the Raute, 

 the Pader, the Alme, and the Heder, and traced the boimdaries 

 of the districts drained by them, and found that nearly two feet 

 of the meteoric waters falling in these districts are expended in 

 the supply of those streams,* Here, then, almost twice as much 

 of the meteoric waters sink into the crust of the earth, as in the 

 district of the Brohlbach, which is so unusually rich in mineral 

 springs.f 



• The Pader I measured at the end of May 1834, when it had not rained 

 for a long time. The Lippe and Alme were measured by Dr Pieper ofPader- 

 born, at my request, in the middle of July, which was remarkable for the un- 

 usual drj'ness of the weather, as Indeed was the whole summer of 1834. It 

 must, however, be observed, that the Lippe loses little of its water in sum- 

 mer; but that the Alme, on the contrary, was very much reduced at the time 

 of the measurement. The copiousness of these rivulets was, therefore, cer- 

 tainly not determined too high. 



t In a few parts oi Germany, where the annual fall of rain is known, does 

 there fall a sufficient quantity to supply the springs, which rise on the west- 

 ern declivity of the Tutoburger Wald? At Coblence, Manheim, Stutlga/rt, Tu. 

 hingen, &c., the yearly fall of rain amounts only to from 20 to 23 inches ; nl 

 Carlsruhe, Giengcn, Ulm, Genkingcn, 24 to 35 inches. See Kiimtz Lehrbuch 

 der Meteorologie, vol. i. p- 458 and following. 



