CHEMICAL SCIENCE. 273 



Two parts of this acid are mixed in a tubulated retort, with two parts by 

 weight of alcohol, and one part of sulphuric acid; after the reaction has 

 taken place, the mixture separates into two strata, the upper of which is 

 washed with water, dried with chloride of calcium, and rectified: it is then 

 butyric ether, has a specific gravity of '9, and boils above '23(P; it is com- 

 posed of CiHoO, CsHrOs- 



To avoid the preparation of free butyric acid, the ether may be prepared 

 by heating the powdered butyrate of lime \vith a "mixture of alcohol and 

 sulphuric acid, skimming of the ether and treating it as above. The essence 

 of pineapples is made by dissolving one part of this ether in eight or ten 

 parts of alcohol. 



Banana Essence is prepared from a mixture of acetate of oxide of amyle 

 and some butyric ether, by dissolving it in alcohol. 



Essence of Raspberries is usually made by mixing acetic ether with an 

 alcoholic essence of orris root. 



Quince Essence. In making this essence, pelargonic acid has to be pre- 

 pared as a first step. This acid is contained in the oil of pelargonium 

 roseum, from which it maybe obtained by combining it with potassa; but 

 more advantageously it is made from oil of rue, by heating it in a retort 

 with nitric acid previously diluted with an equal measure of water, remov- 

 ing from the fire as soon as the reaction commences, afterwards boiling 

 with cohobation until nitrous acid vapors cease to be evolved; the oily acid 

 is then removed, washed with water, combined with potassa, and a neutral, 

 strong- smelling oil separated, after which the solution of pelargonate of 

 potassa is decomposed by sulphuric acid. 



Pelargonate acid is now sufficiently pure for the preparation of the ether; 

 it still contains a resinous substance, from which it may be purified by rec- 

 tification, combining with caustic baryta, and decomposing the crystallized 

 salt with diluted sulphuric acid. Pelargonic acid, by a continued digestion 

 of alcohol, is converted into pelargonic ether, which is obtained purer and 

 in a shorter time by saturating an alcoholic solution of pelargonic acid with 

 muriatic acid gas, washing the separated ether w r ith water, and drying it 

 over chloride of calcium. If the pure ether is sought, this may be rectified; 

 it consists of C4H.50, CisHirOs. 



The pelargonic, also called cenanthic ether, dissolved in alcohol, constitutes 

 the essence of quince. 



Fusel Oil of Wine. Though pelargonic ether is generally called cenanthic 

 ether, many chemists apply the latter name to the pure fusel oil of wine, 

 which, though closely analogous to the former, they assert to be a different 

 compound. This fusel oil is the cause of the persistent smell of all or most 

 wines, and is quite distinct from their bouquet, which in some wines is 

 wanting altogether. It is obtained by careful distillation of the ferment of 

 wines mixed with half its measure of water; a little cenanthic acid may be 

 removed by agitation of the distillate with some carbonate of soda ; the 

 liquid is then heated, the ether rises to the surface, and is obtained free of 

 water by standing over chloride of calcium. Parrish's Practical Pharmacy. 



ON THE ODORS OF PERFUMES. 



At a late meeting of the French Academy, M. Chevreul presented a com- 

 munication upon the mode of action of odoriferous substances. This dis- 

 cussion was intended to recall the publications which this distinguished 



