ACE

ACE

( 4 )

Oxygen in each. Carbon. water.Oxalic 50.56 — 33.5 7 — 22.87

Mucous 36.15 — 33-69 — SO. 16

Tartaric 20.71 — 21.05 — 55.21

Citric 13.41 — 33 .81 — 52 75

Acetic 2.87 — 50.22 — 46 91

These analyses, if correct, give a totally differ-ent idea of the constitution of the acetic acid,compared with the other vegetable acids, fromthat usually entertained. It has been maintainedby Westrumb, Hermbstaedt, Crell, and-others,that the pure acid of vinegar was the ultimateterm of oxygenation of all the vegetable acids,so that any other of these could be convertedinto the acetic by an oxygenating process-Thus Hermbstaedt converted the dry acid oftartar entirely into the acetous, by distillationwith manganese and sulphuric acid. ( See articleAcetous Acid, Ch. Diet. vol. 1, p. 4.3 Buton the other hand the above experiments ofMessrs. Gay-Lussac and Thenard shew thatthe acetic acid is by far the least oxygenated ofthe five vegetable acids here mentioned, butcontains a much larger proportion of carbon,and hence one may expect the acetic acid to beamong the earliest products of any acidifyingprocess going on in vegetable matter. This,they maintain, is supported by actual observa-tion, for the acetic acid is that into which allvegetable and even animal matter is the soonestchanged, whether by distillation or the putridfermentation, or by the action of the nitric andsulphuric acids. How, say they, should thesechanges take place (especially that of wine intovinegar) and no intermediate acid be found, ifthe acetic acid was the most oxygenated.

Pyro-Acetic Spirit. Pyro-Acetic Ether.This substance having already been partiallydescribed in our account of Mr. Chenevix’sexperiments, and aiso having been previouslyexamined by Derosne,’ we shall here add somefurther notice of it,. It is contained, as alreadymentioned, in the product of the distillationper se, of most of the acetites, and it is pro-bably in many cases owing to the admixture ofthis spirit that the specific gravity of the distil-led liquid is so much lessened as to counteractthe increased density which would naturallyarise from a great intensity of acid. M. Derosneobtained it in the following experiments, whichwere also undertaken as a general examinationof the products in the usual way of preparingacetic acid. An earthen retort was filled with

* A«. Chin

411lbs. (French ) of verfigris, and distilled perse, in a very gradual heat kept up for threedays. The products were divided into foursuccessive portions, each of which was keptseparate. The first portion weighing 5 lbs. lOoz.was weakly acid to the last, and of a slight bluecolour.

The second was stronger and deeper coloured,and weighed 6 lbs. 4oz.

The third, was still stronger and more blue,had a much more pungent smell, but ratherempyreumatic. It weighed 7 lbs. 4 oz.

The fourth was slightly y.dlow, had a weakbut very empyreumatic smell, and required avery strong heat to be expelled. It weighed8|- oz.

The united weight of these four liquids was20 lbs. 5 oz. and the cupreous residue in theretort weighed 131b. 14 oz. so that there wasa deficiency of 7 lb. 5 oz. to make up the origi-ginal weight of the verdigris employed.

A large quantity of gas was produced in theoperation, the whole of which was made topass through a separate bottle of distilled waterbefore it escaped, to -which it gave some acidityand a very disagreeable burnt flavour.

The four distilled products were again recti-fied and divided into successive portions, and bycomparing the specific gravity of each with thepower of saturating alkali, it was found thatthe second and third products, or those whichwere obtained at the middle of the first opera-tion, were much the strongest in acid with theleast specific gravity. This intermediate pro-duct being rectified at a gentle heat, gave aquantity of inflammable gas, and a light inflam-mable liquor, but still acid. To separate theacid, solid caustic alkali was added to it insmall portions, keeping the vessel in cold watertill the acid was saturated, when part of theacetited potash crystallized spontaneously, anda light yellowdsh liquor rose on the surface,which was carefully decanted and again recti-fied by distillation at a very gentle beat. Theproduct of this last operation is the Pyro-Acetic Ether.

It is quite clear and colourless, its smellpungent, its taste hot and empyreumatic. Itis lighter than alcohol, very volatile, and pro-duces cold by evaporation. It is highly com-bustible, burning with a flame at first blue,afterwards yellowish white. After its combus-tion it leaves a carbonaceous stain, and if pre-viously mixed with a little water and burned,the water remains slightly acid. It does not

i. tom. G3.