OF THE MEADOW-SWEET. 157 



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 strikitig 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 ori- 

 ginal projjerties, 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 hydi'ogen 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 Avarmed, 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 anhy- 

 drous oil was employed. 



Hydrospiroilate of Ammonia. 



If a concentrated solution of ammonia is poured upon pure hydrospi- 

 roilic 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 com- 

 mon 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 -f- 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 



