B. TERRESTRIAL PHYSICS AND METEOROLOGY. 37 



A still more remarkable ^phenomenon has been recently re- 

 corded by Professor Eversmann, of Kasan namely, the oc- 

 currence of hailstones each containing a small crystal of sul- 

 phuret of iron. These crystals were probably weathered 

 from some rocks in large quantity, and were then taken up 

 from the surface of the ground by a storm, and, when carried 

 into the hail-forming clouds, served as a nucleus for the for- 

 mation of hailstones. 3 C, June 26, 1871,618. 



TEMPERATURE OF THE EARTH IN THE MONT CENIS TUNNEL. 



Advantage has recently been taken of the borings in the 

 Mont Cenis Tunnel to ascertain the interior temperature of 

 the earth, the experiments being instituted at a point in the 

 tunnel which was situated five thousand four hundred feet 

 . from the surface. Here special borings were made to a depth 

 often feet in lateral excavations, which were closed for a con- 

 siderable period of time after the instruments were inserted. 

 The temperature observed at this point was a little over 82^ 

 Fahr. 7 C\ 1871,304. 



INFLUENCE OF BAROMETRIC PRESSURE ON TIDES. 



Dr. Carpenter, in a late communication to Nature, calls at- 

 tention to the neglect, in the late discussions upon the ocean 

 currents, of published observations made upon the influence 

 of variations of barometric pressure upon the sea-level. In 

 this connection he remarks that, according to one author, a 

 fall of one inch in the barometer is pretty uniformly accom- 

 panied by a rise of the sea-level to about thirteen times this 

 amount, or thirteen inches ; and another makes the ratio to 

 be about one to thirteen and a half inches, this being subse- 

 quently corrected to about twelve and three fourths inches. 

 Dr. Carpenter thinks that this relationship of barometric press- 

 ure to the height of the tides may serve to explain a number 

 of anomalous phenomena that have perplexed, observers, es- 

 pecially with reference to unusual rises of tide, and their re- 

 tention at a high level longer than customary. 12 A, April 

 20,1871,481. 



RELATION OF RADIATION IN THE TROPICS TO ZODIACAL LIGHT. 



M. Galliard, of Guadaloupe, states, as the result of numer- 

 ous and exact observations, that between the tropics radia- 



