46o THE POPULAR SCIENCE MONTHLY. 



A. I am sorry to say I do not see my way toward any such sugges- 

 tion. I was merely replying to the general question whether legislation 

 could do anything to cheapen books, and saying that the only thing I 

 thought it could do would be to get, in some way, an extension of area 

 for copyright. 



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THE FOEMATIOI^ OF MOUNTAINS. 



PROFESSOR ALPHONSE FAVRE, of Geneva, has been making 

 an interesting series of experiments to illustrate the formation of 

 the great inequalitiae of the earth's surface by means of lateral thrust 

 or crushing. These he describes and illustrates in a recent number of 

 " La Nature," to which we are indebted for the illustrations which ac- 

 company this article. Professor Favre refers to the early experiments 

 of Sir James Hall with various kinds of cloth, which he made to assume 

 a variety of shapes by means of weights. He speaks of the various 

 theories of the elevation of mountains, and especially of that of H. B. 

 de Saussure, whose term refoulement seems to have meant much the 

 same as that used by M. Favre, ecrasement lateral. 



" The three systems," M. Favre says, " which account for the origin 

 of mountains by forces which push the great mineral masses from below 

 upward, from above downward, or laterally, do not differ so much from 

 each other as at first sight appears. Those geologists who have ad- 

 mitted the system of elevations as the principal cause of modification 

 of the surface of the globe would probably enough admit the forma- 

 tion of depressions as a secondary modification ; and so those who 

 have accounted for these modifications mainly by depression, would 

 probably enough also admit elevation as a secondary factor. Again, in 

 the system of lateral crushing, there is a general depression of the sur- 

 face of the earth, since there is a diminution in the length of the radius 

 of our globe, and yet there result elevations of the ground in the midst 

 of this general depression. 



"The cause of lateral crushing," M. Favre goes on to say, "is owing 

 to the cooling of the earth. It is, in fact, very probable that our 

 globe is at the stage when, according to Elie de Beaumont, ' the mean 

 annual cooling of the mass exceeds that of the surface, and exceeds it 

 more and more.' It must follow that the external strata of the globe, 

 tending always to rest on the internal parts, are wrinkled, folded, dislo- 

 cated, depressed at certain points, and elevated at others. 



"The experiments," M. Favre continues, " which I have made at the 

 works of the Geneva Society for the manufacture of physical instru- 

 ments, resemble much those of Sir James Hall ; they differ notably, how- 

 ever, in two points : 1. The celebrated Scotchman caused the matter 



