Page:Scientific Memoirs, Vol. 1 (1837).djvu/169

 chlorine is passed over one of the metallic combinations, as spiroilide of copper or spiroilide of silver, chloride of copper or silver, and chloride of spiroil are formed without the slightest trace of muriatic acid.

The most striking proof, however, that the oil is really a hydracid is, that when potassium is brottght into contact vjith the oil over mercury and gently warmed, hydrogen is evolved, spiroilide of potassium being formed, from which latter the oil may again be obtained, possessed of all its original properties, by the action of muriatic acid.

The action of the oil and potassium, which at common temperatures goes on but slowly, is by a very gentle heat so much increased, that during the evolution of the hydrogen the combination of the spiroil and potassium is attended with the evolution of heat and light. At the same time not the slightest trace of carbon or of any carbonaceous matter is deposited, and the hydrogen which is evolved is quite pure. If the oil which is employed for these experiments be not quite free from water, evolution of hydrogen takes place as soon as it comes into contact with the potassium; this however ceases (almost entirely) in a few moments: if however the apparatus be now gently warmed, which may be done by gradually bringing near a glowing coal, the evolution of gas begins again in great quantity and with the same violence as when the anhydrous oil was employed.

If a concentrated solution of ammonia is poured upon pure hydrospiroilic acid, the fluid mixture after a few seconds is converted into a solid mass of hydrospiroilate of ammonia, giving out heat and undergoing a considerable increase of bulk during the action: it may be freed from water and excess of acid by washing with alcohol. It possesses a weak aromatic smell resembling a rose, is tasteless, and has a yellow colour. The compound is almost insoluble in water, which nevertheless when left for some time in contact with it, acquires a yellow colour. In common cold spirit of wine the hydrospiroilate of ammonia is only slightly soluble, but on the contrary it is dissolved in great quantities both in hot and cold pure alcohol. If the boiling solution be allowed to cool, hydrospiroilate of ammonia is obtained in transparent delicate tufts of acicular crystals of a light yellow colour. If it be preserved in close vessels in a moist state it is decomposed ; after a short time it becomes gradually black, then semifluid, ammonia is evolved, and an exceedingly strong penetrating odour of oil of roses is perceptible.

At the boiling-point of water, hydrospiroilate of ammonia undergoes no change.

At + 115° it is fluid, melting like wax; heated a few degrees above its boiling-point it volatilizes in the form of a yellow vapour without leaving-any residue and without undergoing any alteration. If solution