1816.] when triturated together. 427 
barytes and anhydrous sul phate of copper triturated together remain 
white. Alcohol does not alter the colour. Water gives it a blue 
colour. 1 must here put the reader in mind that muriate of copper 
with little water is yellow; but, when united with much water, 
blue. 
In these experiments the difference between muriate of lime and 
muriate of barytes consists in this, that the former is soluble in 
alcohol, while the latter is insoluble in that liquid. Solution, then, 
is necessary to chemical action. The water of crystallization of 
sulphate of copper acts entirely as uncombined water, and the 
chemical action of the water is not the consequence of its liquidity, 
but is peculiar to it. 
Acetate of lead in crystals, and anhydrous sulphate of copper, 
when triturated together, remain white, and do not alter one an- 
other. But when acetate of lead and crystals of sulphate of copper 
are triturated together, the mixture assumes immediately a fine 
green colour. Alcohol gives to the white powder a shade of green, 
and water renders it much more green. As acetate of lead in 
crystals decomposes crystallized sulphate of copper, but not the 
anhydrous sulphate, it is probable that it contains no water of crys- 
tallization, at least none in a state capable of acting. Acetate of 
lead issoluble in alcohol, though only in small quantity. 
Acetate of lead and burnt alum just heated, and scarcely cooled, 
being triturated together, produced no alteration on each other, and 
afterwards liquefied very slowly when left in an open vessel. But 
when the burnt alum had been kept for some time in a vessel not 
very well stopped, it very soon became liquid when triturated with 
acetate of lead. ‘The moisture of the atmosphere, therefore, does 
not act directly as a medium of decomposition, but only when it 
has been absorbed by a solid body, and deprived of its fluidity. 
One part of muriate of lime and two parts of sulphate of potash, 
being triturated together, became at first somewhat moist, but 
gradually dried again when left exposed to the air. The taste at 
first was that of muriate of lime, but it became gradually weaker, 
and at last assumed a salt taste. 
Prussiate of potash and sulphate of copper, both heated till the 
water of crystallization was evaporated, when triturated together, 
remained white. Alcohol did not alter the colour. Water rendered 
it reddish-brown. If we take crystallized sulphate of copper instead 
of anhydrous, the mixture on trituration assumes a reddish colour. 
‘The same thing takes place when anhydrous sulphate of copper is 
triturated with crystallized prussiate of potash, ' 
Anhydrous acetate of copper,,being triturated with anhydrous 
prussiate of potash, produced a green colour. Alcohol did not alter 
the colour ; but when left for some days in an open vessel, the 
colour became lavender-blue. Water rendered the colour reddish- 
brown. I may here put the reader in mind that cold alcohol dis- 
solves little or no acetate of copper. . 
Carbonate of ammonia and anhydrous acetate of copper, when 
2H 2 
