ON PYROACETIC SPIRIT. 
203 
tigations, but little more was known of this spirit than its ulti- 
mate composition. This alcoholic spirit is derived from the dis- 
tillation of the fixed acetates and from the decomposition of 
the vapor of acetic acid, and is described under the names of 
acetone, pyroacetic spirit, pyroacetic ether, and mesitic 
alcohol. 
To obtain this liquid in a perfectly pure state, it is recom- 
mended by Liebigt to proceed as follows: — Acetate of lead is 
to be exposed to a high temperature in a retort, and the 
products collected in a receiver. During this process, the 
salt first undergoes the aqueous fusion at the temperature 
of 136° F., boils at 212° F., loses water and becomes solid. 
On elevating the temperature to 536° F., it again melts, 
and loses some acetic acid and pyroacetic spirit; the recipient 
is now to be changed; and, on continuing the heat, pyroacetic 
spirit and carbonic acid come over. The liquid in the re- 
ceiver is to be mixed with an equal volume of water, and 
distilled on a salt water bath; this distillation is to be repeated 
as long as there is any appearance of oil on the distilled liquid. 
To deprive the spirit of water, it must be digested for some 
days upon chloride of calcium in a close vessel, then decanted 
and distilled from some fresh chloride. Pyroacetic spirit, 
thus procured, is a light colorless liquid, of a peculiar odor, 
unlike either alcohol or ether; and miscible in all propor- 
tions with water, alcohol, and ether; is permanent in the 
air, not altered by the alkalies in the cold, and dissolves 
the resins. Its specific gravity is about .80, its boiling 
point is 132° F., and the density of its vapor 2.022. This 
spirit has been analyzed by Liebig, Dumas, and Kane, and their 
results give its composition as three equivalents of carbon, three 
of hydrogen and one of oxygen. The formula expressive of 
its composition, resulting from these experiments, is C 3 H 3 0, 
but Mr. Kane is led to conclude, from his experiments,* that 
the atom of pyroacetic spirit is double of the above, and should 
be represented by the formula C 6 H 6 2 . The formation of 
* Trans. Royal Irish Acad., 16th March and 10th April, 1837. 
