WORKS PUBLISHED BY WALTON AND MABERLY. 



POPULAR SCIENCE. 



LETTERS ON THE PHYSICS OF THE EAETH, 



By H. BUFF, 



Professor of Physics in the University of Giessen. 



EDITED BY DR. A. W. HOFMANN, 



Professor in the Royal College of Chemistry, London. 



Foolscap Svo. 5*. 



This little book consists of a series of Letters, addressed to a person supposed 

 not to have a greater amount of scientific knowledge than is possessed by every 

 man of education. The author has endeavoured to explain, in a manner suited 

 for this purpose, the processes which are at work on the largest scale on this earth 

 of ours, as well as the causes by which they are governed, and their influence on 

 the condition and general features of the surface of the earth. He enters into a 

 full consideration of the phenomena of Gravitation and Heat, the two powers 

 working throughout the entire universe, and which are the mainsprings both of 

 the past revolutions and the present changes of the globe. It is the author's object, 

 not so much to present the man of science with the results of new observations, as 

 to offer to a large circle of readers some assistance towards obtaining a clear view, 

 and more precise notions, of these great natural phenomena. The following are 

 the subjects of the Letters : 



I. Introduction Gravity and its 



Effects. 

 II. Tides. 



III. Heat within the Earth. 



IV. Warm Springs. 



V. Hot Springs and Jets of Steam. 

 VI. Jets of Gas and Mud Volcanoes. 

 VII. Volcanoes and Earthquakes. 

 VIII. Temperature of the Outermost 



Crust of the Earth. 



IX. Temperature of the Lowest Layer 

 of the Atmosphere. Lines of 



equal Heat 



X. Temperature of the Upper Layers 

 of the Atmosphere. The Snow 

 Limits. Glaciers. 

 XI. Temperature of the Waters, and 



their Influence on Climate. 

 XII. Currents of the Sea. 



XIII. Winds. 



XIV. Winds concluded. 



XV. Moisture of the Air and Atmo- 



spheric Precipit 

 XVI. Electricity of the 



tation. 



and Thunder. 



Air, Lightning, 



IIEBIG'S FAMILIAR LETTERS ON CHEMISTRY. 



New Edition. Remodelled and greatly enlarged. Complete, in 1 voL 

 Foolscap Svo. 6s. cloth. 



The object of the author has been to present a sort of bird's-eye view of Chemistry 

 in all its various aspects and relations ; to shew its importance as a means of 

 unfolding the secrets of nature ; and also to shew the influence which it exerts, 

 through its various applications in manufactures, agriculture, and medicine, on the 

 present social condition of mankind. 



After introductory remarks on the importance of chemistry, and on the prin- 

 ciples on which a judicious application of chemistry must be founded, an historical 

 sketch is given of Ihe progress of this science from the time of the alchemists. The 

 general principles of chemistry are then discussed, as chemical affinity, chemical 

 equivalents, the atomic theory, &c. ; also the subjects which are related both to 

 chemistry and natural philosophy, as crystallization, isomorphism, isomerism, 

 condensation of gases, &c. The principles on which some important chemical 

 manufactures, that of soda in particular, are founded, are explained, and the 

 influence on commerce of such applications pointed out. 



A large portion of this work is devoted to a consideration of the various changes 

 to which bodies of organic origin are subject, as fermentation, putrefaction, &c. ; 

 the origin of organic bodies ; the connexion of chemistry with animal physiology, 

 comprising the subjects of nutrition and respiration, with results of the author's 

 researches on dietetics made during the last few years, and observations on the 

 comparative nutritive value of different articles of food ; also the connexion of 

 chemistry with vegetable physiology, comprising the principles by which the use 

 of manures should be guided, and other applications of chemistry to agriculture. 



Bradbury & Evans, Printer*, Wbitefriars. 



