\ 

 o 



8 CALIFORNIA ACADEMY OF SCIENCES. 



heat. It is also decomposed by sulphuric acid with the depos- 

 ition of a white powder which responds to the tests for sulphate 

 of lime. All these solutions, if not too dilute, deposit flaky 

 crystals which have the reactions of free boracic acid. 



During solution there is no effervescence. The finely pow- 

 dered mineral is also soluble in strong solution of chloride of 

 ammonium. 



The muriatic or nitric solution of the mineral evaporated to 

 dryness on a water-bath dissolves on the addition of distilled 

 water without a trace of residue— (absence of silicic acid). 



The nitric solution gives no trace of precipitate with nitrate of 

 silver (absence of chlorine, iodine or bromine) or with chloride 

 of barium (absence of sulphuric acid), or with nitromolybdate 

 solution applied with proper precautions (absence of phosphoric 

 acid). 



The powdered mineral warmed with sulphuric acid gives off 

 no fumes capable of etching glass (absence of fluorine) — warmed 

 with ammonia — free solution of potassa gives no ammoniacal 

 reaction. 



From a muriatic solution, diluted and warmed, nothing is pre- 

 cipitated by sulphurreted hydrogen. 



Ammonia added in excess to an acid solution of the mineral 

 affords a flocculent precipitate of borate of lime, unless the acid 

 solvent be present in great abundance, in which case the form- 

 ation of a precipitate is prevented by the solvent action of the 

 ammoniacal salt generated in the solution. In presence of large 

 excess of ammoniacal salts, ammonia produces no precipitate. 



In these ammoniacal solutions sulphide of ammonium pro- 

 duces no precipitate, but oxalate of ammonia gives a white finely 

 granular precipitate of oxalate of lime. 



This precipitate contains no baryta or strontia perceptible 

 even with the spectroscope. 



Having separated all the lime as oxalate and all excess of 

 ammoniacal salts, phosphate of soda gives not a trace of precipi- 

 tate after brisk agitation of the licpaid and allowing it to remain 

 at rest for twenty-four hours (absence of magnesia). 



The blowpipe test gives slight evidence of the presence of soda. 

 To determine whether this is present in any appreciable quantity 

 I made use of the following process. 



