EXAMINATION OF SALT OF BITUMEN. 



253 



fufed through the folution. To collect this precipitate the fo- 

 lution was filtred as expeditioufly as poflible : the precipitate 

 warned and dried weighed fix grains. 



This precipitate to which the cau(e of the green colour of this was iroa* 

 the folution was owing, after having been (lowly dried, on ex- 

 pofure to air, had the appearance of a dark brown powder. 

 It was foluble in muriatic, fulphuric and nitric acids. Tincture 

 of galls and prufliate of potafli proved it to be an oxide of iron. 

 In order to be pofitive in this refpect, a like quantity of the 

 fame precipitate obtained in a fimilar manner, was diffolved 

 in fulphuric acid, and the folution again decompofed by car- 

 bonate of foda. The carbonate of iron was re-diffolved in di- 

 lute nitric acid, and repeatedly boiled to drynefs in that fluid, 

 till it became completely infoluble, and acquired all the pro- 

 perties of red oxide of iron. 



The faline folution from which this oxide had been feparated, The fluid con- 

 had a ftrong odour of fulphurated hidrogen gas. Its tafte ta, ™ d ,^ l?hu " 

 greatly refembled Harrowgate water. Mercury agitated in con- 

 tact with it loft its brilliancy, and became covered with a black 

 pellicle. Arfeniousacid immerfed into it became yellow ; leaf 

 filver tarniflied inftantly ; nitrous acid, holding much nitrous gas 

 in folution, occafioned a white precipitate ; nitrate of filver, 

 acetite of lead, nitrate of bifmuth, occaiioned black precipi- 

 tates ; muriate of barytes rendered it milky, and a precipitate 

 was depofited which was infoluble in muriatic acid ; prufliate 

 of potafli and tincture of galls had no effect upon it. All thefe 

 experiments (the latter three excepted) fufficiently evinced the 

 prefence of fulphurated hidrogen gas. 



In order to afcertain the contents of the water it was eva-The faline por- 

 porated to drynefs: the fait obtained after having been exa- d ™ ™" ™ un ' ac - 



r - ? ,of foda with a 



mined in the ufual manner, confined entirely or muriate of fmall portion of 

 foda, contaminated with a fmall quantity of fulphuric acid ; ful phunc acid, 

 its weight amounted to 444 grains. To afcertain the quantity The quantity of 

 of fulpnuric acid, the fait was rediflblved in water, and mu-this laft acid was 

 riate of barytes was added till no further precipitate enfued. precipitate br 

 The fulphate of barytes produced when dry, weighed 5 1| muriate of ba- 

 grains, which are equivalent to 14 grains of fulphur. It **2j*% , . . 

 perhaps needlefs to remark that, the fulphuric acid thus found ac jd wa9 ruot 

 did not previously exift in the fait : its production was evidently or gina y fuch, 

 owing to the decompofition of the produced fulphurated ^^fiomniS^, 

 drogen gas, for no veltige of fuch acid could be detected by 

 any other agent, or under other circumltances. 



Sulphur 



