B. TERRESTRIAL PHYSICS AND METEOROLOGY. 123 



Mallet accepts, in general, Sir William Thomson's view that 

 plutonic action results from the dissipation of energy in the 

 shape of terrestrial heat, and that the elevation, folding, and 

 crushing of strata is the result of tangential pressure, origi- 

 nating in the contraction of the earth's crust by slow refrig- 

 eration. The heat is produced locally within the solid shell 

 of our globe in three principal ways : first, by the compres- 

 sion of rocks within the limits of elasticity ; second, the fric- 

 tion by the sliding of beds of rock upon each other; third, 

 the crushing of rock. He attempts to prove these points by 

 showing that the gravitation of the unsupported shell of the 

 earth is adequate to crush into powder all the materials of 

 which it consists, and that the heat produced by crushing is 

 sufficient to account for existing phenomena. A long series 

 of highly accurate experiments and observations upon the 

 crushing of cubes of different rocks gives him the numerical 

 data for computing the exact increase of temperature due to 

 the contraction of the earth. From the observations on the 

 contraction due to cooling, he concludes that the earth's di- 

 ameter, when liquid, must have been greater by one hundred 

 and eighty-nine miles than at present. 4 D, VII., 142. 



THE CLIMATE OF CARINTHIA. 



Prettner has published an important and in many respects 

 a masterly work on the climate of Carinthia. The number of 

 stations he uses amounts to forty-two, being an average of 

 one to every four square miles of the territory. Many of 

 these stations offer him a series of observations that extend 

 over long periods of years. Vierteljahres -JRevue, II., i., 137. 



MATHEMATICAL THEORY OF THE WIXDS. 



An excellent mathematical paper,by Professor Win. Ferrel, 

 of the Coast Survey, has recently been presented to the Nation- 

 al Academy of Science, in reference to the laws of cyclones. 

 The mechanical theory of the cause of these atmospheric 

 disturbances was made known by Ferrel some twenty years 

 ago. In the present paper he is able to refer directly to the 

 great mass of observations that have accumulated since the 

 establishment of national weather bureaus throughout the 

 world, and shows that the average of great numbers of ob- 

 servations completely verifies the mathematical deductions 



