288 REVIEWS. 



An Inquiry into the Nature of Heat, &c. By Zerali (ML urn. 

 London : E. and F. Spon. 



The author considers that the prevalent hypotheses respecting the 

 nature and precise mode of action of heat are unsatisfactory, and, therefore, 

 advances opinions and theories of his own. The subject is one of great 

 interest to all who have to do with the question of steam, the prepa- 

 ration of metals, or any of the other various and important industrial 

 applications of heat. We cpiote the following extract : — 



" Heat is supposed to be extruded from irom by hammering it, 

 until it is red-hot, upon an anvil ; thus (bearing in mind that we are all 

 along dealing with a supposition) savages obtain fire by rubbing sticks 

 of dry wood together ; thus Desaigues, by subjecting fluids to strong 

 pressure, rendered them luminous ; thus compressed air inflames tinder . 

 thus the heads of wooden piles sometimes burst into a blaze under the 

 heavy and rapid blows of a steam pile-driving engine ; thus a cannon- 

 shot, striking an iron armour plate, often throws off a flash of fire, and 

 is afterwards found to be too hot to be handled ; thus the turning, 

 boring, drilling, planning, and polishing of metals are attended with 

 the development of heat ; thus the agitation of the sea in a storm is 

 found to have warmed the water. The same effect being produced also 

 by the compression of water in an hydraulic press ; and thus, in short, 

 heat is supposed to be extruded wherever friction or compression takes 

 place ; and, indeed, wherever atoms of ordinary matter of any kind ap- 

 proach each other. 



" The separation of material atoms cannot, upon the same supposition, 

 be effected except through the agency of heat or electricity, which latter 

 appears to be a linear form of heat, acting in definite directions only, 

 and not in the contagious and diffusive manner of so-called " solar'' 

 heat and the ordinary heat of combustion." 



PUBLICATIONS RECEIVED. 



Enquete sur le Commerce et la Navigation de 1' Algerie (Alger Bas- 

 tide). — A .familiar Epistle to Robert J. Walter (Saunders, Otley, and 

 Co.) — Skin Diseases and their Cure, by a Diaihetical Treatment. By 

 Edwin Payne, M.D. Renshaw. 



