256 



POPULAR SCIENCE MONTHLY. 



were so thin as to be translucent, and we caught the minutest 

 details of their structure, the result of the long work of cen- 

 turies (Salle de Draperies). Accordingly as the calcareous wa- 

 ters were or were not charged with salts of iron, bands alter- 

 nately brown and white were deposited the whole length of 

 the veil, simulating, in their regularity, the stripes of the rich- 

 est tissues of the most complete factories. This hall, of all 

 the caves I have visited, left the strongest impression of the 



marvels to be met 

 with in the bosom of 

 the earth. Leaving 

 this Hall of Draperies 

 with regret, we con- 

 tinued our march, but 

 were soon stopped, for 

 the river went no far- 

 ther on this side. We 

 had traversed nearly 

 five hundred and fifty 

 yards in this resplen- 

 dent cavern, and were 

 now fifty yards above 

 the mouth of the riv- 

 er. Before returning 

 we took a second 

 specimen of water for 

 our studies. It came 

 from a drip which 

 would certainly in 

 less than a year have 

 caused the junction 

 of a stalactite and a 

 stalagmite, and never 

 had we better observed the phenomenon of the union of calca- 

 reous concretions. A third specimen was taken from the dripping 

 roof. As we have mentioned these microbic studies, we will also 

 speak of the results we obtained. 



As a general thing, the culture tubes in which the water from 

 the dripping roof, stalactites in course of formation, and pot-holes 

 in which the water had not been stirred for a long time was put, 

 remained sterile that is, did not contain microbes. But when we 

 examined a drop of water from the vents, or those fine springs 

 that escape from the fissures, or from the pot-holes or lakes of 

 these subterranean rivers, colonies of microbes were developed ; 

 the calcareous filter is no longer sufficient, and while it stops the 

 coarse impurities of the waters that fall on the plateau, it lets the 



-A Passage in the Subteebanean Rivee Mideoi. 

 (From a photograph.) 



