242 DESCRIPTION OF A NITRE CAVE. 



After blowing off large blocks of the rock, they break them 

 into small pieces with hammers, and throw them into kettles 

 containing boiling water ; as soon as the rock falls into sand by 

 the action of the hot water upon it, they put it into hoppers and 

 wash out all the nitre by frequent additions of cold water, this 

 solution is boiled down and crystallized without any mixture of 

 ashes or pot-ash. Sometimes when the mother-water has been 

 very often added to fresh solutions of the nitre, they find it ne- 

 cessary to use a very small quantity of ashes. 



I have been informed by a Mr. Fowler, that he and his as- 

 sociates have made saltpetre at twenty-eight different rock hou- 

 ses or caverns, from which they have obtained about 100000 

 pounds of nitre, all these are situated on the north side of Ken- 

 tucky river, within seventy miles of Lexington. He remarks 

 that he has never seen a rock facing the north or west, which 

 was very rich in nitre. He has always desisted from working 

 a rock when it failed to yield him ten pounds to the bushel of 

 sand. He has often obtained twenty or thirty pounds per bush- 

 el. He assured me that he once discovered a mass of very 

 pure nitre, which was found to weigh 1600 pounds. Mr. Folev, 

 another saltpetre-maker, found one containing 100 pounds; 

 another mass was found on Rock castle, which report says 

 weighed 500 pounds. I have now in my possession a solid 

 mass of native nitrate of pot-ash of singular purity, which 

 weighs three pounds, it is more than four inches in thickness, 

 and is only a small portion of a block of nitre found last sum- 

 mer on Licking river, I have likewise a number of smaller 

 specimens, which I myself procured from the different caves 

 which I visited some weeks ago. These are generally found 

 between the rocks which have fallen from the cliff, or the cre- 

 vices of those rocks which still remain in their primitive situa- 

 tion. The rocks which contain the greatest quantity of nitre 

 are extremely difficult to bore, and are generally tinged with a 

 brownish or yellow ocre colour. Sometimes they contain an 

 oxide like manganese, and sometimes great quantities of iron 

 ore, which resembles the bark of the scaly bark hickory, sur- 

 rounded by a finely powdered brown oxide. At some of these 

 rock houses three hands can make one hundred pounds of good 



