98 Dr. R. D. Thomson, on the Analyses of Minerals. 



Soda, 8-50 9-600 — 8-26 



Potash, — — — 1-57 



Magnesia, — 1*520 1624 — 



Protoxide of Iron,. 0*50 1*200^ 2-682 090 



Alumina, 0*50 0*672/ 



Water, 5*00 2*000 — 889 



98 99-420 104-69 



The formula for this composition is 4 Cal. Si* + NaSi + A.q. 



Since the preceding account was written, I find that Kobell has pub- 

 lished a new analysis of this mineral in his Grundziige der Mineralogie, 

 p. 226, in 1838, or eight years after my analysis was made. His last 

 results agree nearly with mine, and he finds only traces of potash. His 

 numbers are— Silica, 52'34; Lime, 35*20; Soda, 9*66; Water, 2-80. 



These facts are sufficient to point out to mineralogists the name which 

 is entitled to precedence. 



Harringtonite. — The following analyses of Harringtonite, a mineral 

 which gelatinizes with hydrochloric acid, were made by Messrs. Hugh B. 

 Tennent, P. Kater, and John Stevenson : — 



i. n. m. iv. v. 



Silica, 42-11 45-03 3840 40-70 38-00 



Alumina, 2514 26'62 32*52 30'77 32-01 



Lime, 11*52 9*25 1114 10*41 1300 



Protoxide of Iron, 077 060 



Soda, 4*44 3*09 2-44 1-86 2-28 



Potash, trace. trace. trace. trace. 



Water, 1602 1402 1550 1526 1471 



In the first two analyses, the specimen was from a different locality 

 from that represented by the last three, and obviously contained an 

 excess of silica. 



Antrimolite. — This mineral was carefully examined by William Parry, 

 Esq., late of H. M. 4th Regiment of Foot. 



i. n. 



Silica, 43*37 43*47 



Alumina, 26*29 27*32 



Lime, 9*58 1109 



Soda, 4*83 — 



Potash trace. — 



Water 1512 — 



9919 



The excess of lime arises from the calcareous spar which forms the 

 nucleus of the mineral. 



