The Year-Book of Facts in Science and Art - libro usado

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 174 Electrical .Science. ELECTRICITY OF STEAM. On June 9, at the Royal Institution, Prof. Faraday illustrated the extent of our knowledge of the Electricity which accompanies the formation of Steam, previous to showing that when water is poured into a heated metal cup electricity was set free; and that if the vessel, into which the water was placed, was above a certain elevated temperature, no electricity was evolved, in consequence of the water being prevented from contact with the containing vessel by a stratum of steam. The Professor then detailed the first observations made at Newcastle by one of the workmen in attendance on a boiler belonging to the Newcastle and Carlisle Railway, and whose report, that the boiler was full of fire, from the fact that when he placed his hand near it an electric spark was communicated, drew the attention of Mr. Armstrong to the subject, the result of whose investigations was then given. A boiler having been arranged for the purpose of illustrating this subject, the Professor exhibited the production of the spark daring the emission of the steam, and showed most conclusively that the boiler and appendages were charged with negative electricity, while the issuing steam was in the opposite or positive state; that it was necessary that the boiler should be insulated; that the steam should issue through a small aperture; that the material of which this aperture was constructed modified materially the quantity of electricity, wood and the metals having been found by experiment to be the best fitted for the purpose; that the introduction of a small portion of saline matter, as sulphate of soda, into the exit chamber, prevented entirely the elimination of electricity, and even when common water was introduced it had the same effect; that by l...