s., when 51⁄2 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.

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 re-distilled. 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 re-distillation, the pure ether may be obtained.

The boiling point of butyric ether is 238° Fahr. Its specific gravity, 0,904, and its formula C12 H12 O4, or C4 H5 O + C8 H7 O3.

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 {116} 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 here have recommended.

ON A REMARKABLE SPECIMEN OF DECOMPOSED CHLOROFORM. BY JONATHAN PEREIRA, M.D., F.R.S., Physician to the London Hospital.

In July of the present year I received from Mr. Grattan, apothecary of Belfast, a specimen of chloroform, accompanied with a note, from which the following is an extract:—

“Some weeks prior to October 25, 1851, I received from my friend Dr. M’Killen a small bottle of chloroform which he had had of me two or three months previously, and which he stated was subject to very singular changes of color, despite the stopper never having been removed.

At the time he handed it to me the fluid exhibited a delicate pink tint, as though colored with cochineal, and was put aside in a glass case in my shop, of which I kept the key myself. The case was exposed to the diffused light of a large shop window but not to the direct rays of the sun.

Conceiving that the chloroform had by some unobserved means or other become accidentally colored, I took very little interest in the matter, and was not surprised to find it fade gradually, and in a short time become perfectly colorless—and I made a note to that effect upon the 25th of October, {117} concluding that there must have been some error of observation on the part of Dr. M’Killen.

On the 16th of November, however, it again began to change, and the enclosed notes were made, from time to time, as I happened to have opportunity of noticing it.

I tried it under different conditions of light and temperature, without their exerting apparent influence upon it, and being unable to form the slightest conjecture as to the cause or nature of the molecular disturbance which produces these chromatic changes, have taken the liberty of forwarding it to you, should you consider it worthy of attention.

It is at present colorless, and the stopper fast in; and I would only suggest that, before removing the stopper, it might be well to observe for yourself whether changes similar to those I have noticed may not occur again.

The foregoing changes of color were not influenced by any change of temperature between 27° and 86° Fahr., nor by exposure to, nor seclusion from light. The stopper being fast, atmospheric pressure cannot have been connected therewith. Whether it may have been influenced by electrical changes, am not prepared to say.” {118}