Geological Relations of the Atmosphe~e.--T. Sterry Hunt has investigated the geological beariags of the hypothesis of a universal atmosphere, which was proposed by Sir William Grove, in 1843. tie believes that the carbonic acid, which is included in the calcareous and dolomitic rocks, must have had an extra terrestrial origin, and that such an origin can be readily accounted for, by supposing that our atmosphere is part of a universal cosmical medium, which is condensed around centres of attraction in proportions depending on their masses and temperatures, and occupying all the interstellar spaces in a state of extreme rarefaction. Many considerations go to show that the atmospheric changes did not permit a glacial temperature at the sea-level until towards the end of the tertiary epoch. Matthieu Williams used the same hypothesis, in 1870, to account for solar heat, and Hunt employed it, in 1874, to explain the origin of nebulm and the generation of elements by a cosmical chemistry, in accordance with the ideas of F. W. Clarke and Lockyer.--Comptes Rendus.
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Presc,rvation of Iron.--Capt. Bourdon has devised simple forms of apparatus for coating iron with Barff's magnetic lacker. In the course of his experiments he found that the coat of oxide could be formed by the air, in the following manner ; 'The serpentine part of a sheet-iron reservoir, communicates with air which is heated to 120 ยฐ (~48 ยฐ F.). The current of hot air, after circulating through the serpentine, reaches the cylinder which contains the articles to be lackered. The escape-spout communicates with a wateraspirator regulating the flow of air, which should be very gentle. The internal pressure is little more than one atmosphere, the apparatus being in communication with the open air. The temperature of