178 PHYSICAL GEOLOGY. 



Sciences. Translated by A. Leslie. Oeol. Mag. dec. ii. vol. iii. 



pp. 292-297. 

 Records a shower of volcanic dust from Iceland over Norwaj^ and 

 Sweden in March 1875, and describes the character of the different 

 kinds. W. H. D. 



Palissy, B. Eesources : a Treatise on " Waters and Springs." 



Translated by E. E. Willett. Pp. viii, 39. 8vo. Bri/jhton. 

 Written in 1557. Treats of springs, wells, earthquakes, subter- 

 ranean heat, &c. 



Pictet, Raoul. Notice sur la fontaine intermittente de Yichy-les- 

 Bains. [Intermittent Spring of Yichy-les-Bains.] Arch. Sci. 

 Phjs. Nat. t. Ivii. pp. 57-76, pi. i. 

 At about 100 metres below the surface is a sheet of water maintained 

 at a constant pressure of 10 atmospheres ; and at the same depth and 

 under the same pressure is a constant supply of carbonic acid and sul- 

 phuretted hydrogen. On these assumptions the writer explains the 

 way in which this geyser-like artificially-tapped spring acts. G. A. L. 



Vogt, Prof. Carl. Lecture on Yolcanoes. Oeffentlidie Vortriige gelialten 

 in cler ScJuveiz, Bd. 3. Basle. 



Wepfer, G. Ileber das Einfluss der Abkiihlung unseres Planeten auf 

 die Gebirgsbildung, ein Beitrag zur geologischen Dynamik. [In- 

 fluence of the Cooling of the Earth on the Formation of Mountains.] 

 JaJiresh. Ver. Nat. Wiirtt. Jahrg. 32, pp. 156-177. 



Williams, W. M. The Solidity of the Earth. Nature, vol. xv. pp. 

 5, 6. 



To Sir W. Thomson's statements, that rock solidified on the surface 

 must have sunk and that the earth is solidifying from the centre out- 

 wards, replies that the earth is composed of materials of various specific 

 gravity, from which cause they arrange themselves separately when 

 fused, the heaviest metals going to the bottom and the metals of the 

 earths risinar to the surface with the silicon, &c. C. E. D. 



