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 striking proof, however, that the oil is really a hydracid is, 
that when potassium is brought into contact with 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 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 anhy- 
drous oil was employed. 
Hydrospiroilate of Ammonia. 
If a concentrated solution of ammonia is poured upon pure hydrospi- 
roilie 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 alight 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 
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