400 Mr. Faraday on the mutual Action of Sulphuric Acid 
of naphthaline and two volumes of sulphuric acid were shakeit 
together, at a temperature as high as it could be without char- 
ring the substances. The tint, at first red, became olive green; 
some sulphurous acid was evolved, and the whole would ulti- 
mately have become black and charred, had it not been cooled 
before it had proceeded thus far, and immediately dissolved in 
water. A solution was obtained, which though dark itself, 
yielded, when rubbed with carbonate of baryta, colourless 
liquids; and these when evaporated furnished a barytic salt, 
burning without much flame, but which was not so crystalline 
as former specimens. No attempt to form the glowing salt 
from the flaming salt by solution of caustic baryta, suc- 
ceeded. : 
Strontia. 'The compound of this earth with the acid al- 
ready described very much resembled the flaming salt of 
baryta. When dry it was white, but not distinctly crystal- 
line: it was soluble in water and alcohol; not alterable in the 
air, but when heated burnt with a bright flame, without any 
red tinge, and left a result of the usual kind. | - 
Lime gave a white salt of a bitter taste, slightly soluble in 
water, soluble in alcohol, the solutions yielding imperfect cry- 
stalline forms on evaporation: it burnt with flame; and both 
in the air and in tubes, when heated, gave results similar to 
those of the former salts. 
Magnesia formed a white salt with a moderately bitter taste ; 
crystallizing in favourable circumstances, burning with flame, 
and giving such results by the action of heat as might be ex- 
pected. 
Iron. The metal was acted upon by the acid, hydrogen 
being evolved. The moist protoxide being dissolved in the 
acid gave a neutral salt capable of crystallization. This by 
exposure to air slowly acquired oxygen, and a portion of per- 
salt was found. 
Zine was readily acted upon by the acid, hydrogen evolved, 
and a salt formed. The same salt resulted from the action of 
the acid upon the moist oxide. It was moderately soiuble in 
hot water, the solution on cooling affording an abundant crop 
of acicular crystals. The salt was white and unchangeable in 
the air; its taste bitter. It burnt with flame, and gave the 
usual results by heat. 
Lead. ‘The salt of this metal was white, solid, crystalline, 
and soluble in water and alcohol. It had a bitter metallic 
taste, with very little sweetness. The results by heat were 
such as might be expected. 
Manganese. ‘The protoxide of this metal formed a neutral 
crystalline salt with the acid. It had a slightly austere taste, 
was 
