ASTRONOMY AND METEOROLOGY. 331 



He de&ired, he said, to call attention particularly to the variations in 

 the central masses of the lunar mountains, and their physical bearings. 

 Many smaller mountains are simply like cups set in saucers, while 

 others contain only one central or several dispersed cups. But in the 

 centre of many of the larger mountains, as Copernicus, Gassendi, and 

 Theophilus, is a large mass of broken rocky country, 5,000 or 6,000 

 feet high with buttresses passing off into collateral ridges, or an un- 

 dulated surface of low ridges and hollows. The most remarkable ob- 

 ject of this kind which the author has yet observed with attention is 

 in Theophilus, in which the central mass, seen under powers of from 

 200 to 300, appears as a large conical mass of rocks about fifteen miles 

 in diameter, and divided by deep chasms radiating from the centre. 

 The rock-masses between these deep clefts are bright and shining, the 

 clefts widen toward the centre, the eastern side is more diversified 

 than the western, and like the southern side has long excurrent but- 

 tresses. As the light grows on th^ mountain, point after point of the 

 mass on the eastern side comes out of the shade, and the whole figure 

 resembles an uplifted mass which broke with radiating cracks in the 

 act of elevation. Excepting in steepness, this resembles the theoreti- 

 cal Mount d'Or of De Beaumont ; and as there is no mark of cups or 

 craters in this mass of broken ground, the author is disposed to regard 

 its origin as really due to the displacement of a solidified part of the 

 mooft's crust. On the whole, the author is confirmed in the opinion 

 he has elsewhere expressed, that on the moon's face are features more 

 strongly marked than on our own globe, which, rightly studied, may 

 lead to a knowledge of volcanic action under grander and simpler con- 

 ditions than have "prevailed on the earth during the period of subaerial 

 volcanoes. Professor Hennessy inquired whether Professor Phillips 

 had met with any instances during his researches regarding the surface 

 of the moon where the fissures, instead of being narrow at the lower 

 part and growing wider toward the top, were on the contrary narrow 

 above and grew wider toward the lower part. Fissures of this latter 

 description were met with in Java, and indicated a formation arising 

 from external causes, as those described by Professor Phillips were man- 

 ifestly caused by internal disruptive forces. Professor Phillips replied, 

 that he had not met with any instances of fissures of the class spoken 

 of by Professor Hennessy. Any member of the Section who went to 

 see the process of extracting the silver from lead ore would have an 

 opportunity of witnessing, on a small scale, causes in operation pro- 

 ducing exactly similar effects to those observed on the surface of the 

 moon. After the process was completed, and the litharge all blown off 

 from the pure silver, the observer would be very apt to go away, hav- 

 ing seen all he could ; but if he waited for a short time, as the mass 

 of pure silver cooled, be would soon see its surface torn up by explo- 

 sions from within, caused, as he (Professor Phillips) believed, by the 

 extrication of oxygen gas, producing elevations and fissures exactly re- 

 sembling those on the surface of the moon. 



NEW BAROMETRICAL OBSERVATIONS. 



Lately, a large barometer has been erected in the National Astro- 

 nomical Observatory of Santiago de Chili. By this instrument has 

 been observed a singular phenomenon, new to science. We know, 



