CHEMICAL SCIENCE. 225 



fourth of an ounce of concentrated sulphuric acid ; the compound is 

 heated for some minutes, when the butyric acid ether will form a thin 

 layer on the top. The whole is then mixed with half of its bulk of 

 water, and the upper layer taken off ; the remaining liquid being sub- 

 mitted to distillation, yields another quantity of butyric acid ether, 

 which is mixed with that obtained in the first instance, and the whole 

 well agitated with a very diluted, solution of soda, in order to deprive 

 it of all the acid ; which operation should be repeated several times 

 if a very pure ether is desired to be obtained. Care should be taken 

 to use but small quantities of the diluted soda solution at a time, so as 

 not to lose too much ether, this latter being in some measure soluble 

 in water. When large quantities are to be acted upon, the washing 

 water (eau de lavage,) is collected, mixed with an equal volume of 

 spirits of wine, and distilled, by which means a solution of pure buty- 

 ric acid ether in spirits of wine is obtained. 



Butyric acid ether may be also obtained immediately from butyrate 

 of soda, by dissolving 1 part of this salt in 1 part of rectified alcohol, 

 adding 1 part of sulphuric acid, and heating some minutes. The ether 

 collects on the top of the liquid, and is purified by washing with water 

 and with diluted soda solution. 



For preparing pine apple oil, 1 pound of butyric acid ether is dis- 

 solved in 8 pounds to 10 pounds of spirits of wine, which should have 

 been previously deprived of its empyreumatic or fusel oil. Pure 

 French spirits of wine will be found best suited for this purpose. 

 According to the purpose for which the pine apple oil is to be applied, 

 either rectified alcohol of 80 to 90 Tralles, or brandy of 40 to 50, 

 should be used for dissolving the ether. 20 drops to 25 drops of such 

 an extract will suffice for giving a strong pine apple odor to 1 pound 

 of sugar solution, 1 to which some acid, such as tartaric or citric acid, is 

 generally added. 



Bergamot Pear Oil. What is called pear oil is an alcoholic solu- 

 tion of acetate of oxide of amyle, and acetate of oxide of ethyle, pre- 

 pared from potato fusel oil, (the hydrate of oxide of amyle.) The 

 potato fusel oil, or oil of potato spirits (in German, fuseloel,} is the 

 compound distilled over towards the end of the first distillation of 

 spirits made from potatoes, and is an oily liquid of a very strong and 

 nauseous odor. This oil, in the state in which it is obtained from large 

 potato brandy distilleries, is never pure ; but it may be purified by 

 agitating it with a diluted soda solution, when the pure fusel oil collects 

 as an oily layer on the top of the liquid ; this oily substance is then 

 submitted to distillation, and that part which distils over at 100 to 

 112 Reaumer, is collected, and forms the pure fusel oil. 



For preparing acetate of oxide of amyle from this fusel oil, 1 pound 

 of pure ice vinegar is mixed with an equal quantity of fusel oil, to 

 which is added half a pound of sulphuric acid ; the liquid is digested 

 for some hours at about 100, when the acetate of oxide of amyle 

 separates, particularly on being mixed with a small quantity of water. 

 The remaining liquid, when mixed with more water, yields, on being 

 submitted to distillation, a further quantity of acetate of oxide of 



