184 THYSICAL GEOLOGY. 



4. COSMOGONY; MISCELLANEOUS. 



CoNRADs, P. A. Grosse, Gestalt und Dichte der Erde. [The size, 

 figure, and elements of the Earth.] 26 pp. 4to. Cologne. 



Dawkins, W. B. The limits of our knowledge of the Earth. Essays 

 and Addresses by Professors and Lecturers of the Owens College, 

 Manchester. 31 pp. Lond. 

 From considerations based chiefly upon recent researches into the 

 composition of meteorites and of igneous rocks, and upon the results of 

 the application of spectrum-analysis to the study of the heavenly- 

 bodies, the author concludes " that the earth is united by the closest 

 bonds to the heavenly bodies, and that terrestrial change is in a definite 

 direction, in a straight line, so to speak, and not in a circle." He 

 holds " that the forces in play on the surface in ancient times were 

 stronger than they are now," and " that the earth can no more return 

 to her ancient conditions than a man can return to his childhood." 



G. A. L. 



Heeschel, Prof. A. S., and G. A. Lebotje. Notes of some Experi- 

 ments on the Conducting-powers for Heat of certain rocks &c. 

 Bep. Prit. Assoc, Sections, p. 223. 

 The authors have as yet made only preliminary observations ; but 

 these establish the general had conducting-power of rocks, and in some 

 cases confirm the numerical results obtained by Peclet. A. H. G. 



HowAETH, 11. H. Does the Earth receive any thing directly from the 

 sun ? Mem. Lit. and Phil. Soc. Manchester, vol. xiii. pp. 131- 

 140. 



Jannettaz, Ed. Sur la conductibilite thermique dans les roches et 

 dans les corps en general. [Thermal conductivity of rocks.] 

 Compt. Eend. t. Ixxviii. pp. 1202-1205. 



When a point of the surface of a rock is heated, the curves represent- 

 ing the propagation of the heat around that point are, when in the 

 planes of foliation or cleavage, circular, when at right angles to such 

 planes elliptic, the longer axis of the ellipse being aw ays parallel to 

 the intersections of the heated face and the foliation-planes. The 

 relations between the long and short axes in the various rocks experi- 

 mented on are given. A summary, with special reference to schistose 

 rocks, is to be found in Bull. Soc. Geol. France, 3 ser. t. ii. pp. 264- 

 267. G. A. L. 



Peoctoe, R. a. The Past and Future of our Earth. Contemporary 

 Review, vol. xxv. p. 74. 



Tayloe, AjSDeew. On the probability of our successfully calculating 

 the Antiquity of the Earth. Trans. Edin. Geol. Soc. vol. ii. part 3, 

 pp. 402-411. 



