168 PHYSICAL GEOLOGY. 



from cold follow the maxima of the spots ; that this influence of the 

 solar spots is a question of temperature, -whence proceeds, by means of 

 equivalent evolutions and transformations, the vrhole of our terrestrial 

 phenomena ; and that the earthquakes of the W. Indies and Central 

 America seem to be nearly as frequent and as intense at both the 

 maxima and the minima of the spots. G. A. L. 



Reiss, W. [South American Yolcanoes.] Zeitsch. deutsch. geol. 



Gesell. Bd. xxvi. Heft 3, pp. 605-609. 

 Describes visits to the volcanoes of Sangay, Tunguragua, Pelileo, tfec. 



Roberts, T. Yolcanoes and Yolcanic Agency. Proc. Liverpool Geol. 

 Soc. sess. 15, pp. 3-15. 



In 1873 the author found the grottoes near Lake Avernus giving 

 off ammonia, carbonic acid, and sulphurous vapour of a temperature 

 of 180° r., which deposited a yellow crust of basic persulphate of iron. 

 The flow of the gases is eifected by the eruption of Yesuvius. C.E.DeR. 



Rossi, Prof. M. St. de. Bullettino del Yulcanismo Italiano. Perio- 

 dico geologico ed archeologico per 1' osservazione e la storia dei 

 Phenomeni endogeni nel suolo d' Italia. Yol. i. Rome. 



Schmidt, Jul. Yulkanstudien. Santorin, 1866 bis 1872. Yesuv, 

 Bajae, Stromboli, Aetna, 1870. 7 plates. 8vo. Leipzig. 



ScEOPE, G. P. Observations on Mr. R. Mallet's paper on Yolcanic 

 Energy (Phil. Trans. 1873, p. 147). Geol. Mag. dec. 2, vol. i. 

 p. 28. 



Contends that the theory which accounts for volcanic energy by the 

 check given to the escape of internal heat by the accumulation of thick 

 deposits of low conducting power, is perfectly satisfactory, and that 

 therefore Mr. Mallet's explanation is not wanted. Shows that some of 

 Mr. Mallet's views as to the nature of volcanic action, and his state- 

 ment that there are no traces of explosive volcanic action in the 

 Palaeozoic rocks, are incorrect, and denies that we have data enough to 

 enable us to calculate what will be the amount of heat produced by the 

 crushing of rock during the earth's contraction. The controversy is 

 continued on pp. 237 and 342. A. H. G. 



' A review of Messrs. Nasmyth's and Carpenter's book on the 



Moon. GeoL Mag. dec. 2, vol. i. p. 272. 



Comments on the difl'erence between the volcanic manifestations of 

 the moon and the earth. The large craters of the moon are not, like 

 many of the great crater-rings of the earth, the " basal remnants " of 

 volcanic cones, but rather resemble terrestrial crater-lakes, and seem 

 to have been produced by the sudden bursting of enormous bubbles of 

 highly elastic vapour. The craters were afterwards filled by lava that 

 welled up slowly, and in some cases burst through the walls and spread 

 out around in great sheets. The lava-flows on cooling became fissured, 

 and through the rents more lava was forced up, sometimes along their 

 whole length, sometimes only here and there. In the absence of air 

 and water there has been no subaerial denudation, and no coating of 



