Magnesia Carbon Research Articles

II. On the structure of some limestone nodules enclosed in seams of bituminous coal, with a description of some Trigonocarpons contained in them

The authors first describe the occurrence of the limestone nodules, which form a continuous bed in the centre of a thin seam of bituminous coal in the lower part of the Lancashire coal field. The nodules were of various sizes, some weighing many pounds, and caused the coal to bulge out both above and below them, and they were found to be entirely composed of vegetable tissues converted into carbonate of lime and magnesia.

On carbonic acid as a solvent in the process of vegetation

In this paper the author describes the results of experiments made with water saturated with carbonic acid, in many instances condensed by pressure and supersaturated, on the more important inorganic elements of plants, compounds not soluble in water alone, such as phosphate of lime, silica, &c. These results appear to prove that this acid performs in the economy of growing plants a double function; one well-known, already carefully studied, by which, undergoing decomposition in the leaves under the influence of solar light, it supplies carbon to the growing vegetable, and restores oxygen to the atmosphere; the other, hitherto little attended to, in which it acts as a menstruum, conveying certain compounds, insoluble in water, from the soil into the interior of plants to become constituents of their organism. The experiments he details are of two kinds, one set being on single compounds, the other on a mixture of these compounds. The results of the latter seem to prove that water impregnated with carbonic acid is capable of dissolving several substances at the same time, and of keeping them mixed in solution, as carbonate of lime, carbonate of magnesia, phosphate of lime, silica, &c.

Double carbonate of ammonia and magnesia

Double carbonate of ammonia and magnesia

LI. Some observations on the aqueous solution of carbonate of magnesia with excess of carbonic acid, and on the salt which it affords by spontaneous decomposition

LI. <i>Some observations on the aqueous solution of carbonate of magnesia with excess of carbonic acid, and on the salt which it affords by spontaneous decomposition</i>

On the carbonate of magnesia of Southern India

On the carbonate of magnesia of Southern India

An account of further experiments tried at Chatham, for the purpose of obtaining an artificial water cement

Colonel Pasley’s paper was resumed and concluded. The present paper is occupied with the detail of the experiments made by the author in the prosecution of the object of his former inquiry, already submitted to the Royal Society, into the best means of obtaining an artificial Water Cement. These experiments were tried on a larger scale than the former, and were applied more especially to the practical purposes of building. He recommends that the cement should not be applied in two coats, the surfaces being less likely to adhere when this is done, than if the whole cement is applied at once. He succeeded in various ways, in forming cements which appeared to be the same, in all their properties, with natural cements: and he has now employed them in buildings on a scale sufficiently extensive, and in situations sufficiently exposed to the weather, to be brought to the test of experience in the course of time. Some experiments were also made by the author, with the view of forming an artificial lithographic stone, by a calcined mixture of chalk and carbonate of magnesia: but their density could not be rendered such as to answer the purpose intended. On the whole he draws the general conclusion, that in all attempts to imitate the water cements of nature by artificial means, carbonate of lime must be the essential ingredient; next to which in point of importance are silica and alumina. The author succeeded in forming a very good cement by uniting these three ingredients. By the addition of a small proportion either of the protoxide of iron or of the oxides of lead, or of manganese, the qualities of the compound were very much improved ; these latter ingredients appearing to produce a more intimate union of all of them, and a more speedy and permanent induration of the mass.

Additional experiments and observations on the application of electrical combinations to the preservation of the copper sheathing of ships, and to other purposes

Since his former communication the President has had an opportunity of prosecuting his researches upon the above subjects, upon an extended scale, and with results perfectly conclusive and satisfactory. He found that sheets of copper defended by from one 100th to one 150th part of zinc or iron, exposed for many weeks to the full flow of the tide in Portsmouth harbour, suffered no corrosion, and that even one 1000th part of cast iron exerted great protecting influence. Boats and the sides of ships protected in this way were also similarly preserved. Of the different protecting metals cast iron is most convenient, and the plumbaginous substance formed upon it does not impede the electrical action. The President formerly anticipated the deposition of earthy substances upon the negative copper, and this he now found to take place upon sheets of copper exposed about four months to seawater, and defended by from one 50th to one 80th their surface of zinc and iron. They became coated with carbonate of lime and magnesia; but this effect is easily prevented by duly diminishing the proportion of the protecting metal, so as to prevent the excess of negative power in the copper, which then remains bright and clean. The author observes, that many singular facts have occurred in the course of his researches, some of which bear upon general science. Weak solutions of salt act strongly upon copper, but strong ones do not affect it, apparently because they contain little air, the oxygen of which seems necessary to give the electro-positive power to these menstrua; upon the same principle, alkaline solutions and lime-water prevent the action of sea-water on copper, having in themselves the positive electrical energy which renders the copper negative.

XL. On the agency of the carbonate of magnesia in improving bread made from the new flour

XL. <i>On the agency of the carbonate of magnesia in improving bread made from the new flour</i>