Chap 1 alkaline ley, or occasion an immediate precipitate when mixed with nitrate of silver. But when brought in contact with a combustible it burns readily with a green coloured flame, and a very considerable portion of muriatic acid is immediately disengaged in the state of vapour. This fact then so singular was first observed by Gehlen: it has been minutely examined by Thenard. When allowed to remain for a long time in contact with an alkali. it does give out a portion of muriatic acid, and it slowly produces a precipitate in nitrate of silver after the interval of several days, and the quantity of precipitate increases with the time. But in neither case is the ether decomposed, or deprived of the property of giving out muriatic acid when burnt. Composition, Thenard has endeavoured to ascertain the composition of muriatic ether. From the quantity of muriatic acid which disappears during its formation, he has calculated that 100 parts of muriatic ether contain 29-44 of acid. By mixing determinate portions of muriatic ether gas with oxygen gas, firing the mixture, and ascertaining the products, which are only carbonic acid and water, he endeavoured to ascertain the proportion of the other constituents. The following is the result of his examination: 29-44 muriatic acid 36.61 carbon 23:31 oxygen 10-64 hydrogen 100.00* It is generally admitted that it is a compound of one atom of tetarto-carbo-hydrogen and one atom of muriatic acid. Or in a state of vapour its constituents are = 1·94444 ? 2 volumes olefiant gas condensed into two 1 volume muriatic gas = 1.28472 S volumes; which gives 2-153 for the specific gravity, and this number does not differ much from 2-219 obtained by Thenard. If we admit its composition to be so, its constituents will be 4 atoms hydrogen 4 atoms carbon 1 atom muriatic acid 0.5 or 6.15 These numbers appear at first sight to deviate enormously from those of Thenard; but the difference is only apparent. The * Mem. d'Arcueil, i. 341. quantity of carbon approaches very nearly to that given by Sect. IV. Thenard. When we correct the hydrogen by applying the more correct data which we at present possess, Thenard's number will approach much nearer to 6.15 per cent. than it does at present. To obtain the true quantity of muriatic acid, we must add the quantity of oxygen and muriatic acid found by Thenard together, because the supposed oxygen was deduced from an erroneous estimate of the atomic weight of muriatic acid. This will raise the amount of acid to 52.75 per cent. which does not differ much more than 4 per cent. from the calculated number. Even this difference would diminish, if we were to apply the exact data which we now possess to Thenard's experiment. If the preceding estimate of the composition of muriatic ether be correct, it contains no water, and the combustible constituent can neither be considered as olefiant gas nor tetarto-carbo-hydrogen. For it is a combination of 2 volumes of olefiant gas and I volume of muriatic acid gas combined, and condensed into 2 volumes. 2. Chloric Ether. This compound was first noticed by Scheele and West- History. rumb. It has been since noticed by different chemists. Trommsdorf,+ Gehlen,‡ Thenard,§ Berthollet, || Robiquet and Colin, and Despretz,** have made experiments on it in succession. Its nature has not yet been determined in a satisfactory manner; but I have noticed it here in order to draw to it the attention of experimental chemists. It has been frequently called heavy muriatic ether, from the supposition that the chlorine has been converted into muriatic acid. It was prepared by passing a current of chlorine gas through Formation. alcohol or sulphuric ether, till these liquids refused to absorb any more. The alcohol acquired a yellowish-green colour, and a strong smell of muriatic acid. During the process some carbonic acid gas was evolved. When the process was terminated an oily looking fluid had precipitated to the bottom, and when the liquid swimming over it was saturated with potash, an additional portion of this oily matter made its appearance. When ether is employed the oily matter makes its appearance when the saturated liquid is mixed with water. It is to this Opuscula, ii. 135. Gehlen's Jour. ii. 227. Ann. de Chim. et de Phys. i. 426. + Scherer's Jour. iii. 378. Chap. III. oily looking substance that the name of chloric or heavy muriatic ether has been given. Properties. History. Formation. Properties. It is a colourless, thin, oily looking fluid, having, according to Vogel, the specific gravity of 1·134. It is more volatile than water; has a smell somewhat similar to that of nitric ether, an aromatic, hot, and somewhat bitter taste. It does not redden litmus paper. It is very little soluble in water. Vogel added two drops of it to an ounce of water, and several days elapsed before they disappeared. But in alcohol and sulphuric ether it dissolves in any proportion. When assisted by heat it dissolves a little phosphorus. It burns with a greenish-yellow flame, evolving muriatic acid. Muriatic acid likewise makes its appearance when this substance is passed through a red-hot porcelain tube. Nothing very precise has been determined respecting the composition of this ether. Despretz considers it as a compound of 1 volume chlorine, 1 volume tetarto-carbo-hydrogen, or 2 volumes of olefiant gas. But he has not established the truth of this opinion by any satisfactory experiments. It is clear from the experiments of Robiquet and Colin, that its properties are essentially different from the compound of 1 volume of chlorine and 1 volume of olefiant gas, which I distinguished in the last edition of this work (but improperly) by the name of chloric ether. 3. Hydrobromic Ether. This ether was first formed in 1827 by M. Serullas, and has been very imperfectly examined. It was prepared by the following process: Forty parts of alcohol of the specific gravity 0-827 were put into a small tubulated retort, to this one part of phosphorus was added, and finally 7 or 8 parts of bromine were poured in by little at a time. Every time that bromine came in contact with the phosphorus under the alcohol, a rapid combination took place and heat was produced. Hence hydrobromic acid and phosphorous acid were formed. The mixture was now distilled by a gentle heat, what came over being received in a globular glass vessel well cooled. This product being mixed with water, the hydrobromic ether separated and sunk to the bottom. Hydrobromic ether thus prepared is colourless and transparent, heavier than water, has a strong etherial smell, a sharp taste, and is very volatile. It is soluble in alcohol, from which Sect. IV. it is precipitated by water. It does not alter its colour by keeping.* 4. Hydriodic Ether. This ether was discovered by M. Gay-Lussac. He formed History. it by mixing together 2 volumes of absolute alcohol and 1 volume of hydriodic acid, of the specific gravity 1·7, and distilling in a water-bath. He obtained an alcoholic liquid perfectly neutral, colourless, and limpid. When mixed with water, a liquid precipitated in small globules, at first milky, but which gradually became transparent. This liquid was hydriodic ether. What remained in the retort was hydriodic acid, much coloured by an excess of iodine. Serullas formed it by the same process as that which furnished hydrobromic ether; by adding iodide of phosphorus to alcohol in a tubulated retort, and distilling the mixture. The ether was separated from the alcoholic liquid in the receiver by water.+ Hydriodic ether, after being well washed with water, is per- Properties fectly neutral. Its odour is strong, and, though peculiar, it is analogous to that of other ethers. In a few days it acquires a reddish colour, which does not increase in intensity. Mercury and potash instantly destroy this colour by removing the iodine to which it is owing. Its specific gravity, at 72°, is 1·9206. It boils at the temperature of 148°. It is not inflammable, but merely gives out purple vapours when put upon burning coals. Potassium may be kept in it without alteration. Potash does not alter it immediately, neither do nitric, and sulphurous acids, or chlorine. Sulphuric acid renders it instantly brown. When passed through a red-hot tube, it is decomposed, an inflammable carburetted gas is obtained, hydriodic acid evolved, and some charcoal deposited.‡ This ether has not been analyzed; but analogy would lead to the opinion that it is a compound of 1 volume iodine vapour, I volume tetarto-carbo-hydrogen, or 2 volumes of olefiant gas. On that supposition its atomic weight will be 19.375. will be a compound of 10 atoms. And it * Ann. de Chim. et de Phys. xxxiv. 99. + Ibid. xxv. 323. Chap. III. History. Properties. Muriatic, hydrobromic, and hydriodic ethers are probably analogous compounds, consisting of 4 atoms carbon and 4 atoms hydrogen (whether in the state of olefiant gas or tetarto-carbohydrogen is doubtful), united respectively with an atom of muriatic acid, hydrobromic acid, and hydriodic acid. They contain no water, and in this important circumstance differ from the eight following ethers, which seem, like sulphuric ether, to contain water as an essential constituent. 5. Sulphocyanic Ether. This ether was discovered by M. Liebig, and described by him in a Memoir published in 1829.* It was obtained by distilling a mixture of 1 part of sulphocyanodide of potassium, 2 parts of sulphuric acid, and three parts of ether of the specific gravity 0.848. The product of the distillation being mixed with water, an oleaginons liquid separated, the weight of which was about ths of that of the sulphocyanodide employed. At first it swam on the surface, but the alcohol and sulphuric ether which it contained, being removed by repeated washings, it sunk to the bottom under the form of a colourless or slightly yellowish oil. It has a strong smell of assafoetida or cochlearia officinalis, which adheres strongly to every thing which it touches. It is insoluble in water, but it communicates its odour to that liquid. It has a sweetish taste, and leaves an impression of peppermint in the mouth. It is very soluble in alcohol and sulphuric ether. It burns readily, and gives out fumes of sulphurous acid. It begins to boil at 151°, but the boiling point rises to 161°. Its alcoholic solution does not possess acid properties. It is not decomposed either by potash or ammonia. Potassium placed in contact with it, after being rectified from dry chloride of calcium, preserves its lustre for some time; but if heat be applied it becomes covered with a yellow crust soluble in water, and precipitating peroxide of iron red. Hence the crust was sulphocyanodide of potassium. Nitric acid acts upon it with great violence, producing even combustion. Much deutoxide of azote is given out, and the remaining liquid contains sulphuric acid. This ether absorbs chlorine abundantly, sulphuretted hydrogen gas is given out, and the smell of chloride of sulphur becomes sensible. If we add water, and continue to pass chlorine gas, more of it is * Ann. de Chim. et de Phys. xli. 202. |