ALUMINOUS CHALYBEATE SPRING IN I. OF WICHT. Q\ 



magnesian phosphate became slightly brownish during 

 the calcination, owing to the presence of a few particles 

 of iron, the quantity of which was too minute to be 

 ascertained. 



Sect. XIII. Precipitation of the sulphuric and muriatic 

 Acids, with a view to ascertain their quantity. 



Before drawing any ultimate conclusion respecting the Examination 

 contents of the water and the proportions of its ingredients, of*^"^™* 

 I found it necessary to ascertain the quantities of sulphuric 

 and muriatic acids which it contained, in order to enable 

 me to try how far these quantities might coincide with the 

 conclusions obtained by the separation of the basis, and 

 also to assist me, as will be seen hereafter, in forming cer- 

 tain inferences with regard to the alkaline salts. For this 

 purpose I made the following experiments. 



I. To 



ceeded 1 20°, a degree of heat under which this salt appears to retain the 

 whole of its ammonia. These 65*8 grains of triple salt, being exposed 

 for half an hour to a strong red heat in a platina crucible, were reduced 

 to 30 -S grains. The salt appeared then in the form of a friable cake or 

 loose aggregate, a fragment of which, on being urged by the blowpipe, 

 ran into a white opaque vitreous globule, without any farther diminu- 

 tion of weight. In its friable state it was readily dissolved by muriatic 

 acid; in its vitrified form it required heat and trituration. This salt 

 was perfectly tasteless, and showed no attraction for water. With regard 

 to the proportions of acid and base to be inferred from this experiment, 

 it is obvious, that, if 308 grains of phosphate of magnesia contain 

 11 - 82 grains of earth, the remainder, viz. 18*98 grains, represents the 

 proportion of phosphoric acid ; which is equivalent to 38 37 grains of 

 magnesia in 100 of phosphate. In another experiment conducted in 

 a similar manner, the magnesia amounted to 33 7 grains, so that, by 

 taking the mean between these two very nearly similar results, we 

 have the following proportions, viz. 



, 1 • * -*r- > in 100 grains of ignited phosphate of magnesia. 

 Phosphoric acid 6l.S 3 



We may infer therefore, that one grain of phosphate of magnesia, 

 the quantity yielded by twenty grains of residue, indicated o - 385 of 

 pure magnesia 5 and if, according to the statements of Kirwan and 

 Wenzel (which very nearly agree) one hundred grains of crystallized 

 sulphate of magnesia contain seventeen grains of magnesia, 2-2q" 

 grains of that salt will he the quantity corresponding to 385 of a grain 

 of magnesia. And I have the satisfaction of observing, that the pro- 

 portions 



