464 Hidden and Mackintosh — Sodium sul/phato- chloride. 



eific gravity, as taken in naphtha, is 2 '489. Their hardness is 

 about 3 '5. The mineral is very slowly soluble in water and re- 

 mains unaltered in a moderately dry atmosphere. A careful 



analysis by one of us on amounts of 100 and 120 milligrams 

 yielded the following results : — 



CI -. 13-] 2 per cent. 



S0 3 42-484 " 



Na s CO a 1-77 " 



Calculating the chlorine and sulphur as combined with 



sodium only, we get 



XaCl, 21-624 



Xa o S0 __. 75-411 



Na a CO a 1-77 



1-805 



The formula figures out exactly, if the loss and the JSTa 2 CO s 

 are estimated with and as Xa,SO, : i. e., if the loss is Xa 2 S0 4 

 and we consider the Xa 2 C0 3 as replacing a little Xa 3 S0 4 . 



The formula can then be expressed thus : Xa/JS0 4 , iCl 2 ) or 

 3Xa 2 S0 4 . 2NaCl. Excepting the very rare mineral connellite, 

 from Cornwall. England, which is believed to be a cupreous 

 sulphato-chloride (crystallizing in the hexagonal system), we 

 know of no other species related in composition. 



"VTe learn from Dr. A. E. Eoote, in whose stock of Borax 

 Lake minerals we were fortunate enough to find the single 

 specimen of the mineral used in this examination — that he 

 had visited the locality this past summer and that about one 

 month before his arrival a company had been testing the 

 immense alkaline deposit of Borax Lake (San Bernardino 

 County. California), and had drilled an eight inch hole to a 

 depth of over 100 feet. At a depth of 35 feet a small cavity 

 was discovered from which there were pumped out through 

 the drill hole the mineral here announced, with some very 

 remarkable crystals of hanksite. 



But three examples are at present known to us. and two of 

 these of remarkable beauty, are in the Bement collection, the 

 other specimen (a crystal about one inch thick, having long 

 prismatic hanksites implanted upon it), is the one, upon a part 

 of which, this analysis was made. 



It is a matter of interest to note that this mineral, with its 

 anomalous formula, should occur with and be associated upon 

 another mineral, hanksite, having a like strange composition. 



TVe propose for this new mineral the name sulphohalite as 

 suggesting its remarkable composition. 



