Page:Blackwood's Magazine volume 002.djvu/105

1317.] Literary and Scientific Intelligence. 9' LITERARY AND SCIENTIFIC INTELLIGENCE. AT Dawn, in Perthshire, it was lately ob- served, that common Hour Paste has the effect of rendering cast iron quite soft, and similar to plumbago. Dr Thomson sup- poses, that the acid developed by the sour- ness of the Paste, produces this remarkable effect ; and he informs us, that muriate of magnesia produces a similar effect. In the numerous experiments which have lately been made on the strength of Iron Cables, it has been observed, that a very great degree of heat was generated at the time of fracture. It is said, however, that this effect is not constantly produced. The generation of the heat appears to arise from the lateral contraction of the iron, in consequence of the longitudinal force. The fibres or particles of the iron must necessari- ly approach each other in a lateral direction, and therefore the same effect is produced as in the sudden condensation of iron, or the condensation produced by the blows of a hammer. M. Guichardier, hat-maker in Paris, has substituted with success, the hair of the sea otter and the common otter, in place of the hair of the castor, which has long been be- coming scarce. We understand that M. Simonde de Sisvnondi, the celebrated author of the His- tory of the Italian Republics, has written the article Political Economy t and other articles, for the Edinburgh Encyclop edia, conducted by Dr Brewster. M. de Sismondi is at present occupied in correcting the press of the five last vo- lumes of his great work on the History of the Italian Republics. Chlorine Dr Ore of Glasgow has lately finished a very elaborate series of experi- ments on the controversial subject of chlo- rine. Their principal object was to ascer- tain whether water, or its elements, existed in and could be extracted from muriate of ammonia. He has perfectly succeeded in obtaining water from the dry and recently sublimed salt, by methods quite unexcep- tionable. The vapour of such muriate of ammonia being transmitted through laminas of pur 3 silver, copper, and iron, ignited in glass tubes, water and hydrogen were copi- ously evolved, while the pure metals were converted into metallic muriates. This fact is decisive, in the Doctor's opinion, of the great chemical controversy relative to chlo- rine and muriatic acid, and seems clearly to establish the former theory of Berthollet and Lavoisier, in opposition to that more lately advanced by Sir H. Davy with such apparent cogency of argument as to have led public. This decomposition of the salt by the metals, at an elevated temperature, is analogous to the decomposition of potash in ignited gun-barrels, by Gay-Lussac and Thenard. Safety Lamp. Sir Humphry Davy has made a further discovery in regard to com- bustion, which will prove a very great im- provement to his safety lamp. He thus describes it in a letter to the Rev. J. Hodg- son of Heworth : " I have succeeded in producing a light perfectly safe and econo- mical, which is most brilliant in atmospheres in which the flame of the safety-lamp is extinguished, and which burns in every mixture of carburetted hydrogen gas that is respirable. It consists of a slender metallic tissue of platinum, which is hung in the top of the interior of the common lamp of wire guaze, or in that of the twilled lamp. It costs from 6(1. to Is., and is imperish- able. This tissue, when the common lamp is introduced into an explosive atmosphere, becomes red hot, and continues to burn the gas in contact with it as long as the air is respirable ; when the atmosphere again be- comes explosive, the flame is relighted. I can now burn any inflammable vapour, either with or without flame, at pleasure, and make the wire consume it either with red or white heat. I was led to this result by discovering slow combustions without flame, and at last I found a metal which made these harmless combustions visible." Dr Remnant of Plymouth has published a remedy for the bite of a mad dog, which, he says, has been proved by the first medi- cal men of the age, and has stood the test for the last thirty years, though perhaps but partially known in England, if at all. It was discovered in Germany ; and in Dr R's travels through, and stay in that country, (which was some years) he was frequently' a witness of its success on dogs, and other ani- mals that had been bitten by mad dogs. He never saw it tried upon the human spe- cies, but was credibly informed by profes- sional gentlemen of the highest respectabi- lity, who had tried it upon man with the same success, that it never failed as a preventive. It has always been administer- ed as soon as possible after the animal had been bitten. The recipe is as follows " When a dog or other animal is bitten by a mad dog, let the following be given him as soon as possible brass filings, one dram, with white bean meal (calavanceries), in milk or milk broth, well stirred together. The beans are to be burnt brown like coffee, and ground in a coffee-mill, or if finely almost all the chemists of Europe to embrace bruised will do." The same quantity is his opinion. The details of the experiments have b:en communicated some time since to a distinguished member of the Royal Society, and will be speedily laid before the sufficient for the human subject, and no re- petition is necessary, as one dose has by ex- perience been always proved an effectual preventive.