B66 Account of a coinpound Salt, [May, 



manganese, are well mixed, and put into a cast-iron still with a 

 leaden cover, connected by a pipe of the same metal with a 

 wooden base, or chamber, in which there is thinly spread one 

 and a half parts of dry lime, that has been newly slaked and 

 sifted. About four parts of sulphuric acid, of the specific 

 gravity 1*500, are added at intervals through a funnel in the 

 cover of the still ; this causes an immediate extrication of oxy- 

 muriatic acid gas, which passes into the- chamber, and combines 

 with the lime. When the disengagement of gas becomes 

 languid, a fire is applied, and the matter within is well stirred 

 by means of an agitation that passes through the cover ; the heat 

 is now gradually increased, until the gas ceases to pass over, 

 when a plug is drawn from the bottom of the still, which allows 

 its contents to flow out in a half liquid state. 



When this substance remains at rest for a few hours, a dense, 

 black, deliquescent matter subsides, and a greenish yellow 

 coloured liquor floats on the top, and continues to ooze out from 

 the more solid part. The blacit deliquescent substance is in 

 commerce called Bleacher's Residuum ; it is composed of va- 

 riable proportions of sulphate of soda, muriate of soda, muriate 

 of manganese, muriate of iron, muriate of lead, oxides of 

 manganese and iron, silex, alum in, and a small quantity of 

 uncombined muriatic and oxymuriatic acids. 



The greenish yellow part is called sour liquor ; it varies in 

 specific gravity from 1'350 to 1*450, and is composed of muriatic 

 and oxymuriatic acids, sulphate of soda, muraite of soda, muriate 

 of manganese, muriate of lead, and muriate of iron. 



Several vitriol bottles having been filled with this sour liquor, 

 and exposed for some weeks to a temperature that varied from 

 30° to 45° Fahr., a salt slowly formed in groupes of hard crys- 

 tals firmly adhering to each other, which possesses the following 

 properties : 



1. It is of a brownish yellow colour, and a disagreeable 

 metallic taste. 2. It crystallizes in octahedrons, which are 

 sometimes composed of two-four-sided pyramids united by their 

 bases, but are oftener irregular. 3. Its specific gravity is 2*3S0. 



4. It deliquesces in a moist, and effloresces in a dry atmosphere. 



5. When deprived of its acid mother water by being washed, it 

 does not change the colour of vegetable blues, 6. It is soluble 

 in 2*5 times its weight of water at the temperature of 60°, and 

 in -75 its weight of boiling water. 7» With prussiate of potash 

 and iron it forms a yellowish white precipitate. 8. A small 

 quantity of a brown coloured precipitate is slowly deposited, on 

 its solution being dropped into an infusion of nutgalls. 9. Fixed 

 and volatile alkalies form white precipitates with its solution, 

 which soon turn brown when exposed to the atmosphere. 

 10. When exposed to heat, it loses its water of crystallization 

 without undergoing tiie v/atery fusion 5 at a low red heat it 



