OF ARTS AND SCIENCES : JANUARY 28, 1863. 99 



These numbers are not in atomic proportion ; and the mass was a 

 mixture of aluminate and dialuminate. 



In a similar liquid, but of another preparation, alcohol produced an 



amorphous precipitate of neai'ly the same composition. 



The analysis gave 



Ba O 65.70 



Alj Os 34.30 



100 



being intermediate between the neutral aluminate, which requires 



59.86, and the dialuminate, in which is 75 per cent of baryta. 



It is easy to obtain, by a different process, a solution containing 

 alumina and baryta in nearly the proportion of equal atoms, but 

 many attempts which I made to separate the salt proved unsuccessful ; 

 only once was I able to get a body having this composition, and on 

 repeating that process it gave me a different result. 



A mixture of carbonate of baryta and chloride of sodium fuses at a 

 very moderate temperature and without decomposition. If alumina 

 be added to the melted mass, or to the mixture before ignition, a brisk 

 disengagement of carbonic acid ensues. Water dissolves from the 

 mass, beside the chloi-ide of sodium, a considerable quantity of neutral 

 aluminate of baryta, or more probably, as will presently appear, a 

 double salt of aluminate of baryta and -chloride of sodium. The 

 solution is unaffected by caustic alkalies ; acids and chloride of am- 

 monium precipitate the alumina, the latter with disengagement of 

 ammonia. Equal equivalents of alumina and carbonate having been 

 thus fused, and the mass digested with water, the solution gave on 

 analysis, BaO 63.51 



AI2O3 36.49 



Too 

 or from five to six per cent more baryta than is required by the com- 

 position of the neutral aluminate. 



Thinking that the excess of baryta would be precipitated by car- 

 bonic acid before the baryta contained in the neutral aluminate was 

 acted upon, a similar solution was exposed, with frequent agitation, 

 to the air, or a stream of carbonic acid was led through it until with 

 the carbonate of baryta a sensible quantity of alumina was precipi- 

 tated. The liquid then contained 



BaO 62 



AI2 0, 38 



100 



being nearly 3j- per cent of baryta in excess. 



