HYDRO-SULPHURETS. 347 



HYDRO-SULPHURET OF SODA. 



Crystals formed with more difficulty than the preceding ; trans- 

 parent, quadrilateral prisms, acuminated by four planes, bearing a 

 close resemblance to the hydro-sulphuret of potassa.* 



HYDRO-SULPHURET OF AMMONIA. 



1 . The two gases mixed over mercury, or in a bottle, or other- 

 wise, combine ; in equal volumes, they are almost completely con- 

 densed into an odorous cloud, which forms a soft white crystalline 

 deposit on the inside of the vessel, and if it is kept cold by ice, acic- 

 ular crystals will be formed. 



2. The liquid solution is easily formed, but does not crystallize. 



3. It is an excellent test, in examining metallic solutions. 



4. Admitted into the Pharmacopaeia, as a depressing and nausea- 

 ting remedy, in cases of too great action introduced by Dr. Rollo, 

 and used chiefly in diabetes ;f dose, 5 or six drops, three or four 

 times a day, gradually increased, and mitigated, when nausea and 

 giddiness supervene. 



HYDRO-SULPHURET OF LIME. 



1 . Formed, by passing the gas, either through lime water, or milk 

 of lime. 



2. It is formed when sulphur is boiled with lime and water ; but 

 there is also another product soon to be described. 



3. I have often seen distinct prisms formed in the solution made 

 by boiling lime and sulphur to saturation in water ; I am not aware 

 that they have been examined ; if not hydro-sulphuret, may they not 

 be hypo-sulphite of lime ? 



HYDRO-SULPHURET OF BARYTA. 



1 . Formed, as mentioned in the general characters ; but by far the 

 best method is to obtain it from the decomposed sulphate, by char- 

 coal, as described under sulphate of baryta, and soon to be mention- 

 ed again, with particular reference to this subject. 



2. It crystallizes, confusedly, in brilliant plates, which must be 

 dried between folds of blotting paper, and if immediately dissolved 

 in distilled water, they form a colorless solution. 



* It was formerly said to be distinguished, by not forming alum when added to 

 sulphate of alumina, which the other salt would do, but this distinction was indica- 

 ted, probably, before it was known that there is a triple soda^alurn. 



t The physician can prepare this remedy by extricating the gas, under a chim- 

 ney, in the manner already described under sulphuretted hydrogen, and passing it 

 from an oil flask, or bottle, through the aqua ammonia? of the shops, contained in a 

 vial immersed in cold water, or better, surrounded by ice. This remedy has still 

 considerable reputation, and conjoined with a diet of animal muscle, is thought to 

 have produced the most salutary results. I have repeatedly prepared it for phy- 

 sicians, and have always heard a favorable report of its effects, if conjoined with a 

 rigorous diet. 



