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vessel is found to contain portions of sulphureous and carbonic acid. The peculiar substance, in its dry state, does not alter litmus paper; but it reddens it strongly if the paper be moistened. When exposed to the action of boiling water, this body volatilizes through the water, but the remaining liquor contains some muriatic and a little sulphuric acid. Water, therefore, has the power of decomposing, though very slowly, this substance. Indeed if it be left a long timne in contact with a small proportion of water, the liquor becomes strongly acid. Liquid caustic potash assisted by heat, dissolves the peculiar substance without any disengagement of gas. This solution is colourless; when neutralized by sulphuric acid no precipitation takes place from it, which shews that the alkali decomposes the peculiar body. Sulphuric acid, however, produces a slight effervescence, and the liquor exhales a smell of sulphureous acid. On adding to it a solution of sulphate of silver, muriated silver is precipitated,

These results tend to shew, that the substance in question contains sulphur and carbon in combination with oxygen, that is in the state of sulphureous and carbonic acid; for otherwise, some carbon would have been precipitated, or some sulphuret or hydrosulphuret of potash would have been formed.

And again, a portion of the problematic substance being sublimed through ignited lime in a glass tube, it was absorbed by the lime without any vestige of sulphuret of lime being formed, or any carbɔn deposited. And a similar experiment being tried with ignited metallic iron, instead of lime, some muriate of iron and a sulphuret of oxyd of iron* formed, and carbonic acid gas was disengaged. This last

* Sulpbure d'oxidile de fer.

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experiment in particular shewed clearly that the substance in question contains carbonic acid.

The existence of three acids united in this compound, being thus ascertained, their respective proportions remained to be determined. It was by an experiment similar to the last described, that this object was obtained. The outline of this analysis, a minute detail of which would unnecessarily prolong this communication, was as follows:

A portion of the compound, after being weighed with great accuracy, was sublimed through a tube containing some very fine spiral iron wire in a state of ignition, the weight of which was three times that of the compound submitted to analysis. A decomposition took place, the products of which were, as in the experiment above related, muriate of iron, sulphuret of oxyd of iron, and a mixture of the carbonic oxyd and acid gases. These being carefully examined by appropriate reagents, * so as to form an estimate of the quantities of the muriatic, sulphureous, and carbonic acids contained in the peculiar compound, the following ultimate result, respecting the nature and proportions of its constituent parts, was obtained, viz.

Muriatic acid
Sulphureous acid 29,63
Carbonic acid (and loss) 21,63

48,74

100,00

• The proportion of muriatic acid was estiinated by dissolving the muriate of iron in water, and precipitating the acid by nitrate of silver ; that of the sulphureous acid was ascertained by treating the sulphuret of iron with nitro-muriatic acid, and precipitating the sulphuric acid formed by muriate of barytes : froni the known relation between the sulphureous and sulphuric acid, the quantity of the former was easily deduced. And, lastly, the proportion of carbonic acid was gained by reducing the gaseous mixture to the state of carbonic acid, and absorbing this by caustic potash.

From the mode of computation adopted by Mr. Dalton, this triple acid would be composed of two atoms of muriatic acid, to one of the sulphureous, and one of the carbonic acid. It is a remarkable circumstance that the proportions of sulphur and carbon which prevail in the sulphuret of carbon, no longer obtain in this compound; one of the atoms of sulphur being expelled during the formation of the triple acid, and converted into sulphuric acid, which is found in the nitro-muriatic liquor.

The reason why the combination in question does not take place on burning the sulphuret of carbon in oxymuriatic gas, is that this gas does not yield a sufficient quantity of oxygen to acidify the sulphur and carbon, which are to unite with the muriatic acid, so that either nitric acid must be added, or a portion of muriatic acid must be detached from the oxymuriatic gas, by the agency of water, or of some other oxydated body.

It will be necessary to give a name to this triple acid. The combination of the fluoric with the boracic acid has been called fluo-boric acid; but the word fluo does not express the , degree of acidification of the radical, which would be of great advantage in systematic language. In the Essay on the Latin Chemical Nomenclature, which I published some time ago,

I proposed the name of acidum boracico-fluoricum. Upon the same principle, the combination, of the muriatic and carbonic acid, discovered by Mr. J. Davy, would be named acidum carbonico-muriaticum; the combination of the sulphureous and muriatic acid (should such a compound be discovered), would be called acidum sulphuroso-muriaticum; and our triple acid would be acidum muriaticum sulphuroso-carbonicum, a name inconvenient by its length, but perfectly consonant to the principles of Chemical Nomenclature.

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XXIV. On the Means of procuring a steady Light in Coal Mines

without the danger of Explosion. By William Reid Clanny, M. D. of Sunderland. Communicated by William Allen, Esq. F.R. S.

Read May 20, 1813.

The many dreadful explosions of fire-damp, or inflammable air, which have occurred in the extensive and well regulated coal mines of this district, in the course of the nine years during which I have resided in the county of Durham, have often excited my most serious attention; and latterly these explosions have caused the death of so many industrious people, that no individual, possessed of common humanity, can look on the subject with indifference.

Though the improved methods of ventilation have been attended by many solid advantages to the proprietors of coalmines, it is nevertheless worthy of remark, that the increased frequency of explosions clearly demonstrate, that ventilation, in this case, has been no preventive.

Ventilation undoubtedly supplies atmospheric air; but it cannot obviate those inundations of inflammable air, (if I may be permitted the expression,) which, rushing from the old workings and caverns of the coal mine, overwhelm every thing before them. It is evident that ventilation, even in its improved state, has afforded no relief whatever; and here the apparatus, which, in the first instance, I have the

honour to lay before the Royal Society, will be found to afford a good light, unaccompanied by danger.

It very frequently happens that accumulations of carburetted hydrogen gas, mixed with atmospheric air, take place in the wastes, or old workings of the coal mines, and though much precaution is used for keeping this inflammable air confined to its proper places by means of partitions and folding-doors, nevertheless when, by carelessness or accident, this air comes into contact with any ignited substance, an explosion generally takes place.

These explosions happen when the pit-men are occupied in hewing out the coal at the workings, should they chance to open a cavern of unmixed carburetted hydrogen gas. This

gas

for the most part being pent up in a condensed state, rushes forth from a chasm, and forming what is locally denominated a blower, it suddenly mixes with the atmospheric air of the mine, and surrounding the lights of the pit-men, an explosion follows, commensurate with the quantity of hydrogen gas, which is frequently very considerable.

It will be unnecessary to detail the phenomena of an explosion of inflammable air, as they are already sufficiently known; but I hope it will not be unacceptable to the Society to record a few of the more considerable explosions, which have occurred in the course of the last seven years, in this district alone, independently of those which have taken place in other parts of the kingdom within the same time. In the summer of 1805, an explosion happened at Hebburn colliery, by which thirty-two pit-men were killed, who left wives and children in a destitute state, to the number of one hundred and five. About the same time, a colliery at Oxclose blew up, by

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