254 



POPULAR SCIENCE MONTHLY. 



toward the south (Fig. 1). First a wall of stalagmite barred our 

 road ; then we had to scramble over a series of pot-holes, some of 

 which were full of water ; and we then entered the passage of the 

 bowlders, enormous blocks fallen from the roof or the walls and 



NORO 

 A 



Stalagmites des ere 

 .larg 



2yKs^ff,ja 



Fio. 1. Plan of the Subterranean Eiver Midroi. (Drawn by the author.) 



carried along by the waters, worn and polished, which were 

 chaotically piled upon one another along the rapid descent ( Cou- 

 loir des Gouts and Gros Eboulis). Around these blocks we 

 walked upon a shingle of small worn fragments of stalactite, flat- 

 tened by the violence of the waters. There was still a pot-hole 

 more than six feet deep separated from another lake by a mass 

 of stalagmites on which we would have to balance ourselves in 

 order to hoist the boat. It was so narrow that we could not do 

 this, and we had to invent a novel system of ballistics to get the 

 Microbe, which was upward of two hundred yards away, through 

 the difficult passage. And it was very vexing to be stopped, for 

 in a moment the river turned to the west, toward the Roche- 

 male Spring, which we regarded as an issue of the Midroi. With 

 all requisite precautions we took up specimens of the water from 

 this pot-hole, which we planted in culture tubes for the microbio- 

 logical researches we were prosecuting on the water of caverns. 

 The thermometer, which marked 29 C. outside, had fallen to 14 C. 



