Page:Popular Science Monthly Volume 14.djvu/476

From Wikisource
Jump to navigation Jump to search
This page has been validated.
460
THE POPULAR SCIENCE MONTHLY.

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

 

THE FORMATION OF MOUNTAINS.

PROFESSOR ALPHONSE FAVRE, of Geneva, has been making an interesting series of experiments to illustrate the formation of the great inequalities 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 accompany 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, écrasement 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 admitted the system of elevations as the principal cause of modification of the surface of the globe would probably enough admit the formation 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 surface 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 Élie 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, dislocated, 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 instruments, resemble much those of Sir James Hall; they differ notably, however, in two points: 1. The celebrated Scotchman caused the matter