398 KANSAS CITY HE VIEW OF SCIENCE. 



whether positive or negative. Unless some such a state of things exists, Sir John 

 Herschel's statement, " that this force cannot be of the nature of electric or mag- 

 netic forces," must be accepted, for, as he points out, "the center of gravity (of 

 each particle) would not be affected. The attraction on one of its sides would 

 precisely equal the repulsion on the other." Repulsion of the cometary matter 

 could only take place if this matter, after it has been driven off from the nucleus, 

 and the Sun, have both high electric potentials of the same kind. Further, it is 

 suggested that the luminous jets, streams, halos and envelopes belong to the same 

 order of phenomena as the aurora, the electrical brush and the stratified dis- 

 charges of exhausted tubes. Views resting more or less on this basis have been 

 put- forward by several physicists, and in particular by the late Prof. Zollner, 

 who endeavored to show that on certain assumed data, which appeared to him to 

 be highly probable, the known laws of electricity are fully adequate to explain 

 the phenomena of comets. — The Nineteenth Centtiry. 



GEOLOGY- 



REMOTENESS OF THE FINAL CATASTROPHE. 



J. D. PARKER, U. S. A. 



Geology teaches that transitions have occurred in the Earth's crust from the 

 earliest geological times. The larger part probably were operative over long 

 periods and effected slow changes in the ocean level, but produced more or less 

 exterminations among living species. Thus in passing from layer to layer in the 

 rocks one or more species became extinct with a corresponding introduction of 

 new species. At the opening of an epoch many new species would appear, and 

 at the commencement of a period a whole fauna. Creations and extinctions 

 have thus been going on through the whole course of geological history. 



But at longer intervals greater convulsions have occurred in nature. The 

 course of nature seems at times to have completed a cycle terminating in a catas- 

 trophe. A catastrophe (a term which may be retained in geology when properly 

 defined) is not really a retrogression, but a new birth, a more violent transition 

 or unfolding by internal forces, an extermination of life, perhaps an extinction of 

 former races, but an introduction of higher and better forms of life. Such tran- 

 sitions have always resulted in an improved condition of things on the earth, high- 

 er and more perfect organizations having sprung into being. Geological history 

 has thus been z. periodical unfolding from the lower, more elementary and imper- 

 fect toward the higher forms of being. Now if nature does not retrograde, or if 

 the law of progress shall remain in force, may we not reason by analogy that in 



