ceased for a considerable time, the capsule was withdrawn, and another similar capsule filled with dry caustic potash (hydrate of potash), was introduced in a similar manner. The remaining gas (with the exception of a small residue),* was immediately absorbed. Both capsules, after wiping off minute particles of quicksilver which adhered to their surface, were carefully weighed and were found to have undergone an increase of weight, which, of course, expressed the quantity of acid they had respectively absorbed. By combining these results with the examination above described (§ IV. 6.), of the sulphuret of iron found in the tube, the proportions of sulphur and carbon were deduced. Two such experiments were made which yielded very similar results; and by a mode of computation, which will be detailed in the Appendix, we were led to conclude that the alcohol of sulphur, or sulphuret of carbon consists of

If these proportions be compared with the numbers 13 and 5, which are assumed by Mr. DALTON as representing the respective weights of a particle of sulphur and a particle of carbon; or with those of go and 11,4, which are considered' by Sir HUMPHRY DAVY as representing the same substances, we shall find that either of these modes of computation, as well as that detailed in the Appendix, make the above-mentioned proportions of sulphur and carbon, in the alcohol of sulphur, correspond very nearly to two atoms or portions of sulphur, to one of carbon; a result which is perfectly agreeable to the doctrine of determinate proportions. And as the

This small residue corresponded almost exactly to the quantity of air expelled from the tube in which the decomposition had been performed.

sulphur and carbon recovered by our analysis, were precisely equal in weight to the sulphuret of carbon subjected to examination, we are the more confident in believing that it does not contain any other element.

APPENDIX BY PROFESSOR BERZELIUS.

A. Particulars respecting the Mode in which the Proportions of Sulphur and Carbon, in the Alcohol of Sulphur, were established.

Two analytical experiments were made in succession, in the manner described in the paper (§ IV.), with the following results.

Exp. i. 1,05 parts * of sulphuret of carbon produced 0,24 parts of sulphureous acid gas, and 0,59 parts of carbonic acid. The sulphuret of iron found in the tube was dissolved in nitromuriatic acid; the oxyd of iron was precipitated from this solution by caustic ammonia in excess, and the filtered liquor was neutralized by muriatic acid. From this solution, muriate of barytes precipitated a quantity of sulphate of barytes, which, after ignition, weighed 5,6. From Mr. T. DE SAUSSURE's experiments, as well as from inference from the doctrine of determinate proportions, 100 parts of carbonic acid contain from 27 to 27,1 parts of carbon. Therefore the above mentioned 0,59 parts of carbonic acid contain 0,1593 of carbon. From the experiments on the composition of sulphate of barytes, published by myself, 100 parts of that salt contain 13,66 of

The weights represented by these numbers were grammes; so that the quantity of sulphuret of carbon employed in this experiment, was 1,05 gramme, corresponding to about 15 English grains.

sulphur; therefore the 5,6 parts of sulphate of barýtes, are equivalent to 0,765 of sulphur, which, added to the 0,1224 parts of sulphur contained in the 0,24 parts of sulphureous acid gas, make 88,74 parts of sulphur. The sum total of sulphur and carbon is, therefore, 88,74 + 15,93 = 104,67. But the quantity of the sulphur of carbon was 105 parts; consequently there is a loss of per cent. From this experiment therefore, the sulphuret of carbon is composed of 15,7 parts of carbon to 84,83 parts of sulphur.

Exp. 2. 1,175 parts of sulphuret of carbon produced 0,66 of carbonic acid gas, = 0,1782 parts (which is equivalent to 15,167 per cent.) of carbon; and 0,271 parts of sulphureous acid gas = 0,138 of sulphur. In the superior extremity of the glass tube which contained the oxyd of iron, there was found, in that part of the tube which projected out of the stove, a small portion of sublimed sulphur weighing 0,029. The sulphuret of iron found in the tube afforded, by the mode of estimation above related, 6,06 parts of ignited sulphate of barytes = 0,829 of sulphur; therefore the sum total of sulphur is 0,829 +0,29 +0,1380,996 parts of sulphur, which added to 0,1782 parts of carbon, makes 1,1742 parts, or 0,0008 less than the weight of the sulphuret of carbon employed in the analysis.

B. Comparison of the above Proportions of Sulphur and Carbon, in the Sulphuret of Carbon, with those which might be inferred from the laws of determinate Proportions.

The law respecting the combination of combustible bodies between themselves, is that, when two such bodies unite, the proportion in which this combination takes place is such, that if they

be oxydated to a certain degree, they will either absorb an equal quantity of oxygen, or the one will absorb two, three, four, &c. times as much oxygen as the other. As to the metallic sulphurets in general, those which are called sulphurets at the minimum, are so composed that the sulphur requires twice as much oxygen in order to become sulphureous acid, or three times as much in order to become sulphuric acid, as the metallic body requires to become an oxyd or saline basis; and it is on that account, that the sulphurets in minimum produce, by their oxydation, neutral sulphites, or sulphates. Now, by comparing the quantities of oxygen required to convert the sulphur into sulphureous acid, and the carbon into carbonic acid, it appears that the first quantity is twice as great as the latter. The small difference is to be ascribed to the impossibility of obtaining perfectly accurate results in analytical processes so complicated as this; and therefore the sulphuret of carbon may be considered as constituted according to the same law as the other sulphurets; so that the sulphur which it contains requires twice as much oxygen to become sulphureous acid, as the carbon requires to become carbonic acid. Admitting, therefore, that the above views of the composition of those two acids are correct, the sulphuret of carbon would consist of 15,47 parts of carbon, to 84,53 parts of sulphur; and in that case the result of our analysis of the alcohol of sulphur would only differ by per cent. from the proportions obtained by that mode of estimation.

C. Observations on the atomic doctrine of chemical Combination. Mr. DALTON has lately proposed a mode of viewing the subject of determinate proportions, which is distinguished by

its extreme simplicity. From that ingenious mode of expressing combinations, the sulphuret of carbon ought to consist of two atoms of sulphur to one of carbon, since, according to that system, both the sulphureous and carbonic acids are composed of two atoms of oxygen to one of radical. But it is probable, that the gaseous oxyd of carbon consists of two atoms of carbon to one of oxygen, because the quantity of carbon required to convert carbonic acid into carbonic oxyd, exactly doubles the volume of the acid. In this case, and if, according to Mr. DALTON's supposition, sulphureous acid consists of two atoms of oxygen to one of sulphur, the alcohol of sulphur would be, like all the other sulphurets at the minimum, composed of one atom of sulphur to one of carbon.

Sir H. DAVY, in his Elements of Chemical Philosophy, adopts, like Mr. DALTON, the idea that sulphureous acid gas consists of one portion of sulphur to two of oxygen; and agreeably to this, he supposes for instance that the sulphurets of copper, or of silver, are composed of one portion of sulphur to one of the metal. But on the other hand, he considers other sulphurets, such as those of antimony, of iron, and of lead, as consisting of two portions of sulphur to one of the metal, and the sulphuret of zinc would, according to his views, be composed of two portions of the metal to one of sulphur. Yet, notwithstanding this great diversity in the estimation of proportions, all these sulphurets are so constituted that, if the compound be fully oxydated, it remains in a state of perfect saturation. The cause of these apparent inconsistencies seems to be, that the supposed atom, or ultimate particle, or that which is to be regarded as the single portion of a body, requires to be fixed according to some determinate law, before Mr. DALTON'S