Coal, smoke, and sewage, scientifically and practically considered : with suggestions for the sanitary improvement of the drainage of towns, and the beneficial application of the sewage : being the substance of a paper read before the Literary and Philosophical Society of Manchester / by Peter Spence.

  • Spence, Peter.
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Coal, smoke, and sewage, scientifically and practically considered : with suggestions for the sanitary improvement of the drainage of towns, and the beneficial application of the sewage : being the substance of a paper read before the Literary and Philosophical Society of Manchester / by Peter Spence. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    seems not to have been suflQciently if at all observed, namely, the radical difference between the smoke of our dwelling-house chim- neys, which proceeds from our domestic open fires, and that which comes from our tall chimneys, proceeding from closed furnaces. All peisons will have observed that our dwelling-house smoke is seldom dark in colour, being generally of a light grey, approaching to white ; whilst the smoke of our manufactories is almost invariably dark in colour, and when dense it is quite opaque. Now this is a difference not only in appearance but in essential character. The smoke from our domestic fires is a very heterogeneous composition, while that from our furnaces is, I believe, much more simple. Our domestic fires, though vomiting- forth a sufficiently noxious com- pound, have not yet come specially under the ban of our sanitary smoke consumers, and it may be well for the credit of the latter that it is so; for unless' our open fli-es are changed for the close stoves of the Continent, there are no available means of changing the character or results of the process of combustion in that department. In order more clearly to explain the distinctive characters of these two modes of combustion, I may state that there arc two .distinct stages in the decomposition of coal by heat, however that heat is applied. The first is a process of distillation. When coal is exposed to a red heat, or even somewhat under a red heat, its constitution is immediately broken up, and this decomposi- tion is independent of the combustion of the coal, as it takes place equally in close vessels where air is completely excluded. Thus in the closed retorts of the gas works we have the hydrogen, the volatile carbon, the nitrogen, and even the sulphur, expelled; for although this latter body, existing in the coal as sulphide of iron, is not in that form volatile, yet from its affinity for hydrogen it is almost entirely volatilised as sulphuretted hydrogen; and these volatile pro- ducts being all expelled, we have the fixed carbon and the ashes or earthy matters, neither of which can be volatilised by heat, however long continued; the further decomposition belongs to the second stage, and is purely a process of combustion. But do we in the first or distillatory stage, which takes place in our furnaces and open fires as well as in our gas retorts, simply eliminate the volatile constituents of our coal, as hydrogen, carbon 4