^8 THE MAMMOTH CAVE OF KENTUCKY. 



The Cave is divided into two routes, the long and the short; 

 it is the custom to take the shortest first, as a sort of initiation 

 into the mode of procedure. On entering we walk through a 

 tunnel about 7 feet high, and the same broad, when suddenly we 

 find ourselves in an immense cavern, called '' The Rotunda," its 

 greatest height is 100 feet, and greatest diameter 170 feet, the 

 sides are quite smooth, and shew plainly the marks of water action. 

 They are coated with carbonate of lime, and on them hang 

 millions of bats, which keep up an incessant squeaking noise, 

 characteristic of them. 



After leaving the Rotunda, we traverse another avenue about 

 the size of tlie one by which we first entered. Along the sides 

 are remarkable instances of crystallization and the action of 

 running water. The water has scooped out ledges and grooves, 

 which have been partially arched over and connected with gypsum 

 in such a way as to present the appearance of pigeon holes. In 

 this avenue we see the remains of the vats used for making nitre 

 during the war of 18 12-14. The nitre was extracted from red 

 ferruginous clay which forms the floor, shewing that when water 

 was last there it was not flowing at a rapid rate. This clay was 

 brought to the vats in carts resembling the dobbing cart of the 

 navvy, drawn by oxen, their footmarks and the ruts made by the 

 cart wheels remain to the present day. The nitre does not exist 

 in the Cave as nitrate of potash, but as nitrate of lime, and this 

 when acted upon by carbonate of potash is converted into nitrate 

 of potash or ordinary salt-petre. This was the method used by 

 the salt-petre makers in 1812-14. The men employed were 

 chiefly negroes, some of whom did not come out of the Cave for 

 12 months, and when they did were remarkable for the gloss on 

 their skins. It is strange that they should have remained in so 

 long a time as they were never more than a mile from the 

 entrance. 



The presence of nitrate of lime may be due to the decomposition 

 of dead bats, and their refuse ; ammonia would be given off, and 

 the nitrogen of the ammonia^ uniting with the limestone, would 



