The whole of the crude acid is to be rectified with the addition of an ounce of sulphuric acid to every pound.  The distillate is then saturated with fused chloride of calcium, and redistilled.  The product will be about 28 ounces of pure butyric acid.  To prepare the butyric acid or essence of pine-apple, from this acid proceed as follows:—­Mix, by weight, three parts of butyric acid with six parts of alcohol, and two parts of sulphuric acid in a retort, and submit the whole, with a sufficient heat, to a gentle distillation, until the fluid which passes over ceases to emit a fruity odor.  By treating the distillate with chloride of calcium, and by its redistillation, the pure ether may be obtained.

The boiling-point of butyric ether is 238 deg.  Fahr.  Its specific gravity, 0.904, and its formula,

C_{12}H_{12}O_{4}, or C_{4}H_{5}O + C_{8}H_{7}O_{3}.

Bensch’s process, above described, for the production of butyric acid, affords a remarkable exemplification of the extraordinary transformations that organic bodies undergo in contact with ferment, or by catalytic action.  When cane sugar is treated with tartaric acid, especially under the influence of heat, it is converted into grape sugar.  This grape sugar, in the presence of decomposing nitrogenous substances, such as cheese, is transformed in the first instance into lactic acid, which combines with the lime of the chalk.  The acid of the lactate of lime, thus produced, is by the further influence of the ferment changed into butyric acid.  Hence, butyrate of lime is the final result of the catalytic action in the process we have here recommended.

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PREPARATION OF CRUDE PELARGONATE OF ETHYL-OXIDE (ESSENCE OF QUINCE.)

BY DR. R. WAGNER.

It has been believed, until the most recent period, that the peel of quinces contains oenanthylate of ethyl-oxide.  New researches, however, have led to the supposition that the odorous principle of quinces is derived from the ether of pelargonic acid.  In my last research on the action of nitric acid on oil of rue, I found that besides the fatty acids, which Gerhardt had already discovered, pelargonic acid is formed.  This process may be advantageously employed for the preparation of crude pelargonate of ethyl-oxide, which, on account of its extremely agreeable odor, may be applied as a fruit essence equally with those prepared by Dobereiner, Hofmann, and Fehling.  For the preparation of the liquid, which can be named the essence of quince, oil of rue is treated with double its quantity of very diluted nitric acid, and the mixture heated until it begins to boil.  After some time two layers are to be observed in the liquid:  the upper one is brownish, and the lower one consists of the products of the oxidation of oil of rue and the excess of nitric acid.  The lower layer is freed from the greater part of its