lime; the liquid was poured off, and the resin was treated with alcohol containing æther, the alcohol and æther were distilled off, and the residue decomposed by dilute muriatic acid, which afforded a pale yellow precipitate (A), which had an odour of cinnamon; it was filtered, washed with water and dried. The residue insoluble in æther and alcohol was boiled along with the lime in water, which afforded a solution (B); a portion of this (Ba) was decomposed with hydrochloric acid; the yellow precipitate again combined with lime, and then again separated by hydrochloric acid; another portion (Bb) was decomposed with hydrochloric acid, and the yellow flocculent precipitate edulcorated. The portion (C) insoluble in water was edulcorated with hydrochloric acid and water. All these bodies dry with difficulty, and become strongly negative electrical by friction. Their composition approaches that of disacryle:

The author observes, in conclusion, that it was owing to the difficulty of procuring large quantities of pure acroleine, and the injurious action on the eyes, that the examination could not be rendered more complete. Probably we may some day succeed in preparing larger quantities of pure acroleine from other substances. Mannite, which is so nearly allied to glycerine, affords on distillation a product which has the odour of acroleine; moreover, when large masses of sugar are burnt, there is given off a very penetrating odour, which affects the eyes.-Liebig's Annalen for August.

Observations on Legumine. By MM. DUMAS and CAHOURE. The analysis of legumine recently published by M. Rochleder*, and the properties assigned to this product, do not establish its identity with the caseine of milk in a satisfactory manner. According to that chemist, legumine, precipitated by means of weak acetic acid from water in which peas or beans reduced to a pulp had been digested, is partly soluble in potash, and may be separated by this reagent into two products, one of which is soluble in the alkali and is identical with caseine. However, the caseine obtained from milk has been found by all experimenters to contain on an average 15.8 per cent. of nitrogen, while the product described by M. Rochleder afforded him 14 per cent., i. e. one-fifteenth less, which would suppose the product to be so impure that no conclusion can be drawn from it. M. Rochleder, who draws a comparison between the carbon and hydrogen of these substances, has unfortunately neglected to do the same with respect to the nitrogen; moreover, a sample of legumine of bean containing only 53 per cent. carbon, affords in

* See this Journal, p. 540.

the legumine converted into caseine 54.5 carbon, the nitrogen always remaining the same, a fact somewhat difficult to explain.

M. Rochleder has not solved the question relative to legumine. We have at present no doubt that the nitrogenous substance of the Leguminosa contains two distinct substances, of different composition, which occur in variable proportions in the several leguminous plants, or even in the different specimens of one and the same species.

We obtained from hemp-seed, by the same means, a substance which contains the same amount of carbon as the legumine of almonds, but not more than 148 to 15 per cent. nitrogen. If, in fact, there exist two distinct substances, containing the same proportions of carbon and of hydrogen with different quantities of nitrogen, this latter element alone would be susceptible of variation in the several samples analysed. However it may be, we do not think it advantageous to confound at present with caseine a product which is thrown down in the cold by very dilute acetic acid, and of which nine-tenths at least are soluble in concentrated and cold acetic acid, and which is entirely coagulated by heat.-Journ. de Pharm. for November.

Action of Sulphurous Acid on Metallic Oxides.

The following are the results of experiments on the action of sulphurous acid on metallic oxides by M. Vogel.

1st. Red oxide of mercury at first becomes protoxide combined with sulphurous and sulphuric acids, and is afterwards completely reduced to the metallic state by sulphurous acid.

2nd. Pernitrate of mercury is slowly reduced by sulphurous acid, but the reduction becomes perfect with the aid of heat; the protonitrate is reduced in the same manner, but more rapidly.

3rd. Bichloride of mercury is not reduced, under the same circumstances, by sulphurous acid, lower than to protochloride; and when the solution of the bichloride is mixed with a sufficient quantity of sulphurous acid, it is not decomposed by the caustic alkalies added in excess; the mercury remains in solution in the alkaline liquor.

4th. Protochloride of mercury is not reduced to the metallic state by sulphurous acid, but merely to a subchloride of mercury; but subpersulphate of mercury (turbith mineral) is entirely reduced by sulphurous acid.

5th. Neither oxide nor nitrate of silver is completely reduced by sulphurous acid.

6th. The oxides of zinc, antimony and uranium, do not suffer the slightest reduction by sulphurous acid.

7th. The black oxide of copper calcined and left in contact with sulphurous acid, becomes brown protoxide, and the acetate of the oxide becomes acetate of suboxide when heated; the greater part of the copper being deposited in the state of brown suboxide.

8th. Sesquioxide of iron when calcined does not yield any of its

oxygen to sulphurous acid; but the peracetate of iron becomes protoacetate by its action.

9th. Molybdic acid is not reduced by sulphurous acid, but molybdate of potash is reduced to a low state of oxidizement, to the blue compound or molybdous acid.-Journal de Pharmacie et de Chimie, Sept. 1843., and Philosophical Magazine for November.

On the Composition and Origin of the Petroleum found in the Down Holland Moss near Ormskirk. By E. W. BINNEY and J. HAWKSHEAD TALBot.

Although it is by no means uncommon to find traces of an oily matter floating upon the surface of the water that drains out of the peat bogs in the low mosses of Lincolnshire and other parts of England, the authors believe that the occurrence of peat so strongly impregnated with petroleum as that found in Down Holland has not yet been noticed. Baron Thénard* describes this substance as follows:-" Petroleum less fluid than naphtha, of which it seems to be a modification, brownish-black, almost opake, of a strong tenacious odour, unctuous to the touch; specific gravity 0-854, burns, leaving but little residue, and gives, on distillation, an oil similar to the naphtha. Found it at Gabian, near Berziers, in Auvergne, near Clermont, in Switzerland near Neufchatel, in England at Örmskirk in Lancashire, and Amiano in Italy, in Sicily, in Transylvania, in India, &c. It often floats on water; the sea is sometimes covered with it near the Volcanic Isles of Cape de Verde." Mr. J. E. Bowman has analysed a specimen of the pitchy peat possessing an empyreumatic smell, found under an old sward field in Formby about six inches beneath the surface. Its organic constituents in 100 parts were 60.31 C, 8.86 H, and 30.83 O. This, when compared with the analysis of common peat made by Regnault, 60-89 ̊C, 6·21 H, 32.90 O, shows that the former differs from the latter in having lost 58 C and 2-7 O, and gained 265 H. Mr. Bowman found 73 C united to 69 H in a specimen of the dark-coloured empyreumatic oil (petroleum) skimmed from the surface of a pool of stagnant water which drained from the upper bed of peat where that deposit is covered by a bed of about fifteen inches of drift sand. On taking Professor Johnson's formula of the composition of lignine .... And deducting the equivalents of the pitchy peat before analysed....

There is a loss of......

}

160 C

128 H 128 O

128

55

145

This shows the removal of 15 atoms of carbonic acid gas and 73 atoms of oxygen, supposing the pitchy peat to have been produced from woody fibre. But this specimen being a mechanical admixture of peat and petroleum, little value can be attributed to it. The better way to show the true results of the decomposition is to compare the analysis of the petroleum with that of woody fibre.

Woody fibre...
Petroleum.

Loss

* Traité de Chemie, tom. iii. p. 445.

The pitchy deposit found under the arable fields possesses little or no smell, the volatile oil affording it having doubtless been evaporated. Its specific gravity is greater than that of the petroleum, from the circumstances of its having lost some of the lightest constituents of that oil, and also combined with a considerable amount of oxygen. On first inspecting the peat, the authors imagined that the petroleum had its origin from some spring which flowed up through the moss from a fissure in the strata underneath; but after examining these deposits, composed of silty clay, sand, till, and most probably portions of the new red sandstone formation, and finding the lower bed of peat not only destitute of petroleum, but quite dry, they became convinced that the oil could not have come from below. They next considered that it might possibly proceed from a spring which rose out of the higher land at Halsall or Down Holland, and then flowed down into the moss; but the peat on the eastern side, although moist and nearest to the source of any spring from that part (if such were the case), was totally destitute of petroleum. The only remarkable feature connected with the upper bed of peat, is the western portion of it being covered up with a bed of sand, and being probably sometimes subject to an infiltration of sea-water according to Mr. Harkness's information. These circumstances, added to the fact of the petroleum being found most plentifully at the edge of the sand, lead the authors to the conclusion that it is produced by the decomposition of the upper bed of peat under the sand.

The chemical process by which such singular effects have been produced is a subject more fitted for the consideration of the chemist than the geologist; but the authors suppose that the petroleum is the result of slow combustion in the peat, and has been produced by a process partly analogous to that which takes place in the destructive distillation of wood in close vessels, where, owing to a total absence of oxygen, the combination of hydrogen and carbon, in the form of hydro-carbons, is effected.-Proceedings of the Manchester Geological Society for 1843.

How to distinguish between real and spurious Gilding.

In many cases in which it is difficult to employ the usual test for gold, especially for distinguishing between real and spurious gold leaf, gilt paper, &c., M. Altmüller recommends the application of mercury, which rubbed in on true gilding immediately produces a white spot, while it has no action on spurious gold (consisting of alloys of copper). On the other hand, an acid solution of mercury in nitric acid leaves untouched real gold, and produces a white spot on the spurious. The thinnest layers of gold, which it is frequently impossible to detect by means of aqua regia, are immediately recognised by this test. The coating of varnish must be removed previous to its application.-Allgem. Wien. Polytech. Journ., 1843, p. 225.

749

INDEX TO VOL. I.