With a view to account for the presence of mineral oil underground in certain parts of Europe and in Pennsylvania, some ingenious persons have assumed that the oil is a decomposition-product of long-buried organic remains. But the answer to this is that the oil is found in very old strata ‘where but few organic remains can have existed.’ Mr D. Mendelejeff, a foreign chemist, having visited the Pennsylvania wells, puts forward his opinion on this interesting question: The substance of the earth having been condensed from vapour, ‘the interior of the earth must consist largely of metals (iron predominating) in combination with carbon. Wherever fissures have been produced in the earth’s crust by volcanic action, the water, which of necessity made its way into the interior, and thus came into contact with metallic carbides at high temperatures and pressures, must have given rise to saturated hydrocarbons, which have ascended in the form of vapour to strata where they condensed,’ and thus formed the oil. Captain Calver, R.N., has by command of the Admiralty surveyed the Thames below Woolwich to ascertain whether the discharge of the sewage of London into the river has created obstructions in the channel. The captain has published his report, and a very discouraging report it is, for it makes known that shoals have formed, and are forming, which in course of time will completely stop the navigation of the river. In this we have a proof that it is a mistake to send the solid portion of sewage into a stream, in the hope that it will be effectually carried away by the tide. It is not carried away; but is deposited at the bends, and in the eddies, with detriment to health as well as to the water-way. Engineers who contend that none but neutralised liquid sewage should pass into a river are manifestly in the right. To discharge the solids is a waste as well as a mischief; and if it goes on, the whole of the land will some day be utterly starved for want of nitrogen. Some theorists argue that it won’t pay to attempt to convert the solids into a fertilising material. The answer to this is the experience gained at Aylesbury, where the solid part of the town sewage is separated from the liquid by precipitation; is converted into a fertiliser, part of which is used on the town-farm, and the surplus, in the form of a dry, scentless powder, is sold at three pounds ten shillings the ton. A single grain of oats, sown on land treated with this powder, produced seven thousand grains from one root, and other grains yielded varying numbers down to two thousand. The powder on analysis seems poor; but its richness of productive power may be judged of from the foregoing statement.