Fusel oil is a colorless oily fluid, which possesses at first not an unagreeable odor, but at last is very disgusting, producing oppression at the chest and exciting cough.  It has a sharp hot taste, and burns with a white blue flame.  It boils at 296 deg.  Fahr., and at temperature of -4 deg.  Fahr. it becomes solid, and forms crystals.  Its specific gravity at 59 deg.  Fahr. is 0.8124, and its formula C_{10}H_{12}O_{2}.  On paper it produces a greasy stain, which disappears by heat, and when exposed to the action of the air it acquires an acid reaction.  Fusel oil is slightly soluble in water, to which it imparts its odor; and soluble in all proportions in alcohol, ether, volatile and fixed oils, and acetic acid.  It dissolves phosphorus, sulphur, and iodine without any noticeable change, and also mixes with caustic soda and potash.  It rapidly absorbs hydrochloric acid, with the disengagement of heat.  When mixed with concentrated sulphuric acid, the mixture becomes of a violet-red color, and bisulphate of amyloxide is formed.  Nitric acid and chlorine decompose it.  By its distillation with anhydrous phosphoric acid, a fluid, oily combination of hydrogen and carbon results.  By oxidation with bichromate of potash and sulphuric acid, fusel oil yields valerianic acid, which is used in medicine, and apple-oil, employed as a flavoring ingredient in confectionery.

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ESSENCE OF PINE-APPLE.

BY W. BASTICK.

The above essence is, as already known, butyric ether more or less diluted with alcohol; to obtain which pure, on the large scale and economically, the following process is recommended:—­

Dissolve 6 lbs. of sugar and half an ounce of tartaric acid, in 26 lbs. of boiling water.  Let the solution stand for several days; then add 8 ounces of putrid cheese broken up with 3 lbs. of skimmed and curdled sour milk and 3 lbs. of levigated chalk.  The mixture should be kept and stirred daily in a warm place, at the temperature of about 92 deg.  Fahr., as long as gas is evolved, which is generally the case for five or six weeks.

The liquid thus obtained, is mixed with an equal volume of cold water, and 8 lbs. of crystallized carbonate of soda, previously dissolved in water, added.  It is then filtered from the precipitated carbonate of lime; the filtrate is to be evaporated down to 10 lbs., when 5-1/2 lbs. of sulphuric acid, previously diluted with an equal weight of water, are to be carefully added.  The butyric acid, which separates on the surface of the liquid as a dark-colored oil, is to be removed, and the rest of the liquid distilled; the distillate is now neutralized with carbonate of soda, and the butyric acid separated as before, with sulphuric acid.