The magnetic purification of river water and the report of the sewage committee of 1864 / by Thomas Spencer.
- Spencer, Thomas
- Date:
- 1865
Licence: Public Domain Mark
Credit: The magnetic purification of river water and the report of the sewage committee of 1864 / by Thomas Spencer. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![I may now state the reason why the new purifying substance is termed Magnetic Carbide. Tlie word Carbide is adopted as being associated with tlie following improvement in the manufacture, and which to some extent denotes the compo- sition of the material. Having only a limited quantity of pie- pared oxide at command for my first experiments, it had to be fre- quently removed from one filtering apparatus to another, as well as mixed with other ingredients. Under these circumstances its brittle granules were liable to be reduced to a powder, which might interfere Avith the ]jassagc of water. It was therefore, desirable to devise some mode of rendering them harder and less friable, in the event of their being subjected to much washing. All know that a small proportion of carbon hardens metallic iron into steel. With this analogy in view, it was worth while trying whether a similar result might not be obtained with an oxide. I confess my hopes of success were not great, as I knew of no instance of carbon as such, entering into chemical combination with a metallic oxide. However, the experiment was tried by adding charcoal powder to magnetic oxide, and subjecting both in a retort for several hours to a dull red heat—as is practised in the cementatory process for the formation of steel. At the ter- mination of the experiment the oxide was found to have not only absorbed carbon, but to have lost its objectionable brittleness. In short it had become thoroughly hardened into—what I may be allowed to term—an oxide steel; though without any tendency to further oxidation on exposure to moisture, or, at a temperature less than high red heat. In short, this compound body turns out to be practically as indestructible under all possible atmospheric influences, as gold or platinum. At first, I was led by some of the experiments to believe its combination with carbon, took place only in atomic proportions. Tiiis I now find is not invariably so; nor is it necesssary, because a comparatively small proportion of carbon—from 2 to 3 per cent.—effects the object desired; more being detrimental to its purifying power. With regard to the word magnetic, it is prefixed to that of carbide, because, but for the power of the substance to attract oxygen to its surface, the purifying action would not take place. The commercial term Magnetic Carbide therefore, seems appropriate, inasmuch as it designates an essential property, as well as an element of its composition. Ac- cording to strict chemical nomenclature its technical name ought to be, Ferrosoferric-carbide, but this is far too pedantic for a](https://iiif.wellcomecollection.org/image/b22278576_0027.jp2/full/800%2C/0/default.jpg)
