Chap. 15.] [ 99 ] 



CHAP. XV. 



"OF THE STRONTHIAN, JARGONIC, AND .ADAMAN- 

 TINE EARTHS. 



The Swttijb or Strbnthian Earth difcwered by Dr. Craivford.Oftbe 

 Jargonic Earth. Adamantine Earth. All of thefe fcarce Minerals. 



THE SCOTTISH or STRONTHIAN earth was long 

 unnoticed, and was confounded with the calca- 

 reous genus, to which it bears a near refemblance. It 

 was firft brought under the confideration of the learned 

 by the late Dr. Crawford. It has hitherto been only 

 found in a mild (late, united with fixed air, which (like 

 limeftone) it lofes by a ftrong heat, when it forms L 

 kind of lime. This lime, however, is more foluble in 

 water than that produced from common calcareous 

 earth, and is fpecifically heavier. It decompofes vi- 

 triolated tartar, but is itfelf decompofed by barytic 

 lime. It alfo decompofes folutions of common gyp- 

 fum, and of nitrated or muriated calx. 



Vitriolic acid dropped into this lime water produces 

 an immediate precipitation, which it does not in com- 

 mon lime water. The earth itfelf is found in large 

 lighter whitifh green mafies. Its fpecific gravity is 

 from 3.4. to 3.644. 



Of the JARGONIC earth, the only fpecies yet known 

 is the ftone called the Jargon of Ceylon, which is ge- 

 nerally of a grey or greenim olive colour. The cryf- 

 tallization prefents either right-angled quadrangular 

 prifms furmounted by pyramids, or oftohedrals. The 

 external luflre is cafual, but the internal is ftrong, in- 

 clining to the metallic. Its Ipecific gravity is 4.416. 

 In its qualities it more refembles argil, than any other 

 H a kind 



