BORON. 16.5 



quantity of sulphuric acid to heat in a platinum 

 crucible. The boracic acid is disengaged in 

 the state of fluoboric acid, and the base of the 

 borate remains combined with sulphuric acid. 

 In the alkaline borates the base, when converted 

 into a sulphate, is soluble in water, and may 

 therefore be obtained in a separate state and its 

 weight determined. I had recourse to this 

 method, in order to determine the weight of 

 soda in borax, my previous analysis of this salt 

 having been obviously incorrect. (1.) 19 grains 

 of borax being slowly raised to a red heat in a 

 platinum crucible till they ceased to lose water, 

 were found to have sustained a loss amounting 

 almost exactly to 9 grains. (2.) 19 grains of 

 borax, and 9%5 grains of very finely pounded 

 fluor spar, intimately mixed together, were 

 made up into a paste with sulphuric acid in a 

 platinum crucible, and after digesting for 24< 

 hours were exposed to a strong red heat. The 

 matter remaining in the crucible was white, and 

 weighed about 26 grains. This matter was 

 digested in water, which dissolved the sulphate 

 of soda, together with a little of the sulphate 

 of lime. This water was mixed with oxalate 

 of ammonia to throw down the lime. It was 

 then filtered, evaporated to dryness, and the 

 residual salt exposed to a red heat. It weighed 

 within rmnyth part of 9 grains ; indicating 4 

 grains of soda. Thus it appears, that 19 grains 



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