VOL. LXXXIX.] PHILOSOPHICAL TRANSACTIONS. 403 



boiled, without any apparent dissolution. I added about 2 gr. of sugar, but with- 

 out effect, except that its colour became yellowish. I now boiled the fluid, till it 

 all evaporated in reddish-yellow vapours: there remained a very black, thick, gluti- 

 nous mass, smelling like burnt sugar. Having added 3 oz. of water, the greatest 

 part of the blackish matter rose to the surface, and the water appeared only a little 

 tinged. The fluid part indeed became brown by boiling; but after rest and subsi- 

 dence, it again got clear. I filtered it, a; then poured 2 oz. more distilled water 

 on the residuum, and, after digesting, boiling, and filtering, added the filtered 

 fluid, b, to the former, a. After this treatment, there remained 2gr. of 

 residuum, c. 



Exper. 32. Having caused the fluid a, b, of exper. 31, to evaporate, it yielded 

 a salt greyish-yellow mass, which very quickly attracted the moisture of the air. 

 Being again dissolved in water, and saturated with pot-ash, a considerable quan- 

 tity of whitish earth was precipitated, very much resembling talc. 



Exper. 33. The residuum, c, of exper. 31, which, besides its insolubility and 

 lightness, had much of the external appearance of coal, was now thrown on melted 

 nitre, and it deflagrated. I placed a 2d crucible with melted nitre close to it, and 

 having, at the same moment, thrown into one the above-mentioned residuum, 

 and into the other a quantity of common charcoal pulverized, I could not observe 

 the smallest difference in effect. Very little difference was also apparent, as to 

 the residuum, (3, of exper. 22, c, of exper. 24, and that of the following 

 experiments. 



Exper. 34. To obviate the objection, that sedative salt alone would perhaps 

 deflagrate with melted nitre, I made that experiment also, but in vain. Not the 

 smallest deflagration took place, even when both were melted together for many 

 hours. — Exper. 35. Another objection may be made, namely, that in distilling 

 the muriatic acid from manganese, part of the latter had passed over with the 

 acid ; and, in the frequent distillations of the sedative salt, had been deposited on 

 it, and thus deflagrated. But, on throwing fresh pulverized or solid manganese, 

 either such as is usually sold, or quite pure, heated to redness, into melted nitre, 

 not the smallest deflagration took place. 



Exper. 36 to 50. Instead of the interrupted heat used in the foregoing experi- 

 ments, I now exposed 4-oz. of the salt, with 3 oz. of the oxygenated muriatic acid, 

 to a continued heat of between 200° and 300° of Fahrenheit. The fluid had 

 nearly evaporated in 24 hours. I changed the phial, towards the close of the 

 operation, for another, that the former might be gently heated, and the fluid by 

 that means be poured back, with the greater safety, on the warm salt, through 

 the tube of the retort. In this manner, during an uninterrupted fire of 14 days, 

 the acid was 14 times distilled, and returned on the salt. On the 3d day, yellow 

 spots appeared. On the 4th, some particles of oil or fat were discovered, 

 swimming on the surface of the fluid in the phial; which particles, after cooling 

 and emptying the phial, adhered to its sides, so as to obscure its transparency, 



