1824.] Neio Scientific Books. 157 



various experiments conducted upon different principles was, 

 that the two are essentially distinct. The part of the effect inter- 

 cepted by glass being shown to have a greater relation to the 

 texture of the surface on which it acts, and the part transmitted 

 to the darkness of colour. 



17. Explosive Engine. 



An engine of a very remarkable kind is, we understand, about 

 to be brought into public notice, which, if it answer the high 

 expectation of its inventor, may ultimately supersede the use 

 of the steam-engine. The patents for England and Scotland 

 are, we believe, both completed, so that we may expect soon 

 to hear the particular details of its construction. 



At the lower end of a small cylinder is placed a minute ap- 

 paratus for producing oil gas. As the gas is generated, it 

 elevates a piston so as to admit as much atmospheric air as, 

 when combined with the oil gas, would render the mixture ex- 

 plosive. When the piston has reached this height the gas is 

 exploded, and the mechanical force of the explosion is employed 

 to drive machinery. Experiments have, we understand, been 

 actually made with this power, which was employed to force 

 up water to a considerable height. 



Our readers will no doubt be reminded by this brief notice, 

 of the ingenious invention of the Rev. Mr. Cecil, by which the 

 power is obtained by taking advantage of the vacuum created 

 by the explosion of a mixture of hydrogen and common air. — 

 (Cambridge Transactions, vol. i. part 2.) Mr. Cecil suggested 

 in his paper that the expansive force of the explosion might 

 also be employed ; but his machine was not founded on this 

 principle. — (Edin. Jour, of Science.) 



18. Electricity produced by Congelation of Water. 



When water is frozen rapidly in a leyden jar, the outside coat- 

 ing not being insulated, the jar receives a feeble electrical charge, 

 the inside being positive, the outside negative. If this ice be 

 rapidly thawed, an inverse result is obtained, the interior becomes 

 negative, and the outside positive. Grothus. — (Jour, of Science.) 



Article XIX. 

 NEW SCIENTIFIC BOOKS. 



PREPARING FOR PUBLICATION. 



The History of Mollusca, containing a Description of all the Species 

 of Recent and Fossil Shells. By J. E. Gray, MGS. This work will be 

 published in Parts, each forming a complete work, illustrated with 

 figures of all the new species, and furnished with Indices, and a geo- 

 logical list of the fossils. 



