had somehow disappeared. M. Morin found this in the water over which the compound had originally been formed; for although both gases may have been well purified, this water always becomes strongly acid, and in fact, being saturated with bi-carbonate of potassa, evaporated to dryness and ignited, the chloride of potassium produced was found to contain half the chlorine which had been employed in forming the oily fluid.

Hence the true theory of action is as follows: four atoms of carburetted hydrogen being acted upon by two atoms of chlorine (equal volumes), one of the former gave its hydrogen to one of the latter, to form one of muriatic acid, and its carbon to the other atom of chlorine, to form an atom of proto-chloride of carbon. This atom of proto-chloride, combined with the remaining three of carburetted hydrogen, forms the chloric ether*; and upon consideration it will be found, that such a compound would give by decomposition the proportion and kind of gases before stated to

occur.

Action of Chlorine on Alcohol.-As alcohol and ether may be considered as hydrates of carburetted hydrogen, M. Morin then closely investigated the effect of chlorine upon them. In the alcohol experiment, the chlorine being disengaged in a matrass, then passed through a vessel containing chloride of lime, next through that containing the alcohol, next to this was a vessel containing water, and ultimately a fourth with a solution of chloride of lime; the third vessel was to absorb any muriatic acid formed, and the fourth to saturate any carbonic acid which might be disengaged. When the chlorine was passed very slowly, and the alcohol was very pure, the whole of the gas was absorbed, and a greenish oily liquid was deposited at the bottom of the vessel. Gradually the absorption of chlorine diminished, but did not cease until several days had passed, after which the bubbles were increased in bulk whilst traversing the liquid. There were then two liquids in the vessel, the lower third was oily, whilst the upper part was very acid and fuming. Either could be coloured green by a slight excess of chlorine. The increase in weight indicated the chlorine absorbed, and by saturating the acid liquor with bi-carbonate of potassa, the quantity of muriatic acid produced was easily determined. Of the two liquids, the lightest was found to precipitate by water, and to be a solution of the heavier in acid; the quantity thus dissolved was estimated by comparative experiments. The quantity of carbonic acid produced was as nothing, the trace existing probably came from the manganese. The experiment proved that chlorine combined with alcohol in a volume equal to that of the hydro-carbon present, estimated in the same state; that half the

We have ventured to alter the number of atoms, &c., referred to by M. Morin in illustration, without, however, altering the sense of the statement. M. Morin doubles the atom of carbon, and calls it vapour, &c.; the consequence is, that in the very passage altered, the theoretical impropriety occurs of saying, that bi-carburetted hydrogen is composed of two atoms of hydrogen and one of carbon.-—Ed.

chlorine became muriatic acid, and that the other half formed a substance of the same specific gravity as the hydro-chloride of carbon. Hence, it may be concluded that chlorine acts on alcohol as it does on olefiant gas; that the composition of the substances obtained in both cases is the same, and that the water of the alcohol is not concerned in the action. A good result can only be obtained in operating at temperatures close to 32°, in allowing only a very slow current of chlorine, and in effecting complete saturation. The operation will soon appear terminated, but in such cases a very variable oily product will be obtained.

Action of Chlorine on Ether. The same kind of experiment, and with the same apparatus, was then made with ether, also a hydrated hydro-carbon. By keeping the temperature at 32°, or below; moderating the current of chlorine; and continuing the operation until the saturation was perfect; all the muriatic acid produced passed into the third vessel, or that containing the water. In place of the ether, nothing remained but a green liquid impregnated with chlorine, and of the specific gravity of chloric ether.

The muriatic acid produced represented half the chlorine: the oily matter was equal to what the hydro-carbon in the ether could have produced, as olefiant gas with chlorine. The quantity of carbonic acid evolved was quite insignificant; the water of the ether was inert during the action, and in fact, the action of chlorine is the same whether olefiant gas, alcohol, or ether be used. Although all proceeds successfully if every precaution be taken, yet inattention easily gives erroneous results. If the saturation be incomplete, the oily matter varies in density and quantity. If the current of chlorine be rapid, ether is carried off into the water and escapes the action. If the temperature rise, the muriatic acid and ether react upon each other, and muriatic ether is produced.

The substances thus produced, though alike in composition, vary in some properties, and principally in taste and odour; these differences, it is supposed, may be due to a little sweet oil of wine. That made with the gases has a sweet penetrating taste and agreeable odour; those with alcohol and ether have an acrid taste, resembling more that of peppermint; in colour and some other qualities they differ slightly. They agree, however, in specific gravity, which is between 1.22, and 1.24; in extreme solubility in alcohol and ether; in being almost insoluble directly in water, but soluble by means of muriatic acid, and remaining in solution after the acid is neutralised. All produce by combustion a green flame, and abundant vapours of muriatic acid*.

6. BROMIDE OF CARBON.

The following account of this substance is extracted from a work on bromine and its chemical combination, by C. Lewig.

* Ann. de Chimie, xliii. 225.

Bromide of carbon may be prepared in two ways; according to the first method, bromine is mixed with alcohol at 36° Baumé. The mixture heats strongly, and if bromine is still added, a moment of sudden effervescence supervenes, accompanied with disengagement of vapours of hydro-bromic acid and free bromine. After the liquid has cooled, there is added an alcoholic solution of caustic potash until discolouration is produced; water is then poured in, and the alcohol is evaporated at a gentle heat. When the liquid begins to cool, there separates a small quantity of a yellow oil, heavier than water, and immediately after a concrete crystalline matter. The alcoholic solution may also be diluted with a large quantity of water, and in this manner the concrete substance equally separates with the oil.

This combination, however, may be obtained in greater quantity by the following process. Bromine is put along with ether for a certain time, and the mixture is then distilled. At first there only passes hydrobromic acid, and then comes a very clear oil, which falls to the bottom of the liquid that has already passed. When the distillation has been continued for some time it is interrupted, pure potash is added to the residuum, and it is diluted with water. There is then deposited a voluminous white mass which is washed with water upon a filter. It is then melted at a very gentle heat, and allowed to harden by cooling.

This bromide of carbon forms white opaque scales, greasy to the touch, like camphor, and friable. Its smell is highly aromatic, resembling that of nitric ether; its taste is sharp, like that of peppermint. In the fluid state it is transparent and colourless. It burns as long as it is in contact with flame, and disengages vapours of hydro-bromic acid. It is heavier than water, melts at a slight degree of heat, evaporates at 212° F., and sublimes, forming acicular crystals, having a pearly lustre. It is but feebly dissolved by water, to which it communicates its smell and taste. When the water is at 122° F., it is dissolved, and at a higher degree it is in part evaporated with the vapour. Alcohol and ether easily dissolve it, and the solutions are not rendered turbid by nitrate of silver. Alkalies have no action upon it, even at the boiling temperature. Sulphuric, hydrochloric, and nitric acids have no effect upon it. When the melted bromide of carbon is submitted to a current of free gas, chloride of brome is immediately formed. On heating it with the oxides of iron, copper, zinc, &c., there are obtained metallic bromides, and carbonic acid gas. By making it pass these metals in the state of vapour, there are obtained metallic bromides and charcoal. It is to this latter property that M. Loewig has had recourse for analysing the bromide of carbon, which is composed of 9.01 carbon, and 91.99 brome, the atomic weight of the latter being =941.1*.

Edin. Nat. Journal, ii. 233.

7. PREPARATION OF PHOSPHURET OF LIME.-(Dr. Coxe.) I employ two Hessian crucibles, some of the inner members of a nest. The larger of the two has a hole bored through its bottom, and a test tube of a suitable size luted in with clay. The phosphorus is put into the test tube, the top of which is loosely covered with a piece of broken crucible to prevent the small pieces of quicklime from running down into it. The lime is then put in so as to fill this crucible and partly fill the upper smaller one, which serves as a cover to it, and is luted on with some fine clay a little moistened. The cover has also a small hole in its top to afford an outlet for the air, or volatilised phosphorus, if there should be any occasion for it. The whole is now placed upon the grate of a furnace, with the test tube projecting through and appearing below, and a charcoal fire kindled around it. The phosphorus may be kept cool if it should be thought necessary, by making the tube dip into the water, contained in a tin cup attached to the end of a stick. When the crucibles and their contents are thoroughly red hot, a chafing dish is substituted for the tin cup, and the phosphorus rising in vapour produces the desired change. The phosphuret should be preserved in a sealed vial. The same crucibles may be used a number of times*.

8. IODIDE OF POTASSIUM A GOOD TEST FOR ARSENIC-CURIOUS COMPOUND PRODUCED.

Professor Emmett of Virginia has recommended the iodide of potassium, or iodine alone occasionally, as a useful test for white arsenic. He found that when the iodide was added to a solution containing only 2.8 per cent. of arsenious acid, or 1.8 per cent. of arsenite of potassa, or when iodine alone was added to a solution containing 2.8 per cent. of arsenite of potassa, an immediate precipitation took place. If the precipitation be performed with drops upon a glass plate, then dth of a grain of arsenic is sufficient for the purpose; the precipitate, when gradually formed, is white, adheres with great tenacity to the glass plate, and then may be thoroughly washed, and will present the following characters. Concentrated nitric acid changes the white colour to a dark brown, purple, or even black, from free iodine; and starch added at the same time, becomes deep blue. Strong hot sulphuric acid does the same; when cold, it merely produces a bright yellow, the latter effect is produced by strong muriatic acid. Metallic salts are not likely to cause errors in the use of this test, because, if originally present, they are separated by the carbonated alkali used to dissolve the arsenious acid. The presence of coffee, tea, milk, and other liquids, does not seem materially to retard the precipitation.

The substance thus formed appears to be a curious compound. It resembles arsenious acid in solubility and precipitation; thus, Silliman's Journal, xvii. 349.

hot water dissolves about 5.3 per cent. and deposits nearly one half on cooling. It requires a much higher heat than white arsenic for its volatilisation (550° Fahrenheit), and at 600° is decomposed, giving off first arsenical fumes and then evolving iodine. On analysing the substance it turned out to be a compound of

Notwithstanding the novelty of such a compound, in which it is impossible to tell whether the white arsenic acts the part of acid or base, although it is present nearly to the extent of five atoms, and where no analogy to the composition of a double salt appears obvious; yet Professor Emmett observes there are facts from which its existence must be inferred. Thus iodide of potassium, even when added in great excess, does not precipitate the whole of the arsenite of potassa, nor is it capable of diminishing the alkaline reaction; on the contrary, when arsenite of potassa is so far neutralized by free acetic or arsenious acid as not to affect turmeric paper, it acquires this property by the addition of iodide of potassium, apparently in consequence of a union between the latter substance and the excess of arsenious acid, which while dissolved had the power of counteracting the alkaline effect: other considerations lead to the same result. If subsequent experiments should establish the existence of such a compound, it will be a solitary but striking example of what may be considered a chemical hybrid *.

9. AMMONIA IN NATIVE OXIDE OF IRON.-(Boussingault.) Vauquelin shewed that rust of iron contained ammonia, and Chevallier shewed that the natural oxide of iron also contained the same alkali. As the oxides the latter worked with came from a distance, it might be urged that they had acquired ammonia by the way; for if rust formed within houses absorbed ammonia, so also might native oxides acquire that alkali in its transit from place to place. M. Boussingault, therefore, sought to ascertain whether the natural oxides of iron gave the substance immediately after their extraction from the earth.

In the mine of Cumba near Marmato, a large vein of hydrated oxide of iron in syenitic porphyry is worked as a gold ore. In a part of this mine, called por a fuera, where the work proceeds with activity, about a foot of mineral was broken down at the end of the excavation so as to expose a fresh surface, and then a hole was bored in the very middle of the vein; after having been carried eight inches deep, the powder of the ore was collected carefully in a basin, placed under the hole, and touched by nothing but the tool. Four ounces of this ore were then bruised and rubbed in distilled

* Silliman's Journal, xviii., 58.