OF ARKANSAS. 179 



soft dolomite, and excrements of bats or birds. It is very easily reduced 

 to a fine powder, which feels soft between the fingers. 



Composition dried at 2 10 deg. F: 



Matter insoluble in hydrochloric acid 11.510 



Oxide of iron, phosphates of alumina, lime and 



magnesia 5.908 



Lime 22.929 



Magnesia 14.884 



Potassa 1.106 



Chlorine 0.062 



Sulphuric acid 1.375 



Nitric acid 0.973 



Carbonic acid 38.487 



Organic matter, and loss 2.790 



100.000 

 The air-dried earth lost 1.681 per cent, of moisture at 240 deg. F. 



Another portion of the air-dried earth was treated with distilled water, 

 until fresh portions of the solvent ceased to take up any fixed matter. 

 The solutions were united, evaporated to dryness, and the residue sub- 

 jected to analysis. 100 parts of the air-dried earth yielded 3.936 parts of 

 solid, soluble matter, at 220 deg., F., which had the following compo- 

 sition: 



Lime 1.013 



Magnesia 0.180 



Totassa 0.066 



Chlorine 0.012 



Sulphuric acid 1.338 



Nitric acid 0.956 



Organic matter and water 0.371 



3.936 



Hence it follows, that from 100 lbs of the air-dried earth 1.791 lbs of 

 nitre may be obtained, which consist of 0.956 lbs of nitric acid and 0.835 

 lbs of potassa. 



No. 41. Nitre-determination, in a nitre earth, labeled " laminated nitre 

 earth from a cave in Marion county." 



100 parts of the air-dried earth were found to yield 9.892 parts of solid 



