198 Miscellanies. 



and physical constitution of these bodies, and of the phenomena resulting 

 from their motions ; and the third, of the theory of gravitation. The 

 fourth part is composed of problems in practical astronomy, to be solved 

 by means of the tables that are given at the end of the treatise. Under 

 the first of these four divisions, the author treats of the construction and 

 use of the more important astronomical instruments, gives the theory of 

 corrections, and then applies Kepler's laws to the determination of the 

 places and motions of the bodies in the solar system ; a chapter also is 

 here added on the measurement of time. The subject of eclipses and 

 occultations falls of course under the second division. It will perhaps be 

 thought by some, that the department of physical astronomy, which forms 

 the author's third division, might have occupied, with advantage, a some- 

 what larger portion of his work. In elementary treatises on astronomy, 

 designed for students, this branch of the subject has, we think, not gen- 

 erally held that degree of prominence which it deserves, as a highly use- 

 ful means of mental discipline. 



So far as we have been able to examine the treatise of Prof Norton, it 

 has appeared to us an accurate and well digested work ; and, accompa- 

 nied as it is with a valuable collection of astronomical tables, we think it 

 can hardly fail to be well received by the public. 



24. Postscript to p. 71. — The remarks on the subject of the rocks of 

 the western part of the state of New York, being all secondary, require 

 some explanation. According to Buckland they are mostly transition, 

 also most of the Cattskill and Allegany Mountains; because he does not 

 admit a class of lower secondary rocks. See Bridgewater Treatise, Vol. 

 I, p. 55. According to Conybeare and others, the encrinal limerock is a 

 lower secondary rock. See pp. 352 to 356. But this appears to be an 

 error, arising from his considering the transition encrinal and the cherti/, 

 as the same rock. That the rock at Fort Plain, on the Erie Canal, is the 

 genuine encrinal limerock of Conybeare, no one will question, who fol- 

 lows up the Otsquago Creek one mile. I could refer geologists to nu- 

 merous localities. No Europeon geologist, who admits a lower secondary 

 class, would include in the transition class, any rock in the state of New 

 York, west of the counties of Oswego, Oneida, Montgomery, Schenec- 

 tady, Albany, Greene, and Ulster, if he was convinced, that the encrinal 

 limerock is that which extends through Amsterdam, Fort Plain, Trenton 

 Falls, &c. to Sackett's Harbor on Lake Ontario. A. E. 



25. The Mammoth, (Mastodon? Eds.) — The following statement is so 

 interesting and important that we give it a place, although it is deficient 

 in responsibility. We resquest the unknown author to communicate with 

 us directly ; and having made a similar experiment successfully, in a very 



