An Experiment in Mountain-Building: Part II.

Abstract

I n 1903 the Society did me the honour of publishing a short paper on this subject. I may, perhaps, just repeat that Sir James Hall many years ago, and others since, have illustrated the formation of folded mountains by placing layers of cloth under a weight, and then compressing two of the sides so that the cloth was thrown into folds. Since then, other and more complete, experiments of the same kind have been made by Favre, Cadell, Daubrée, Willis, Ruskin, and others. In these investigations the compression was from two sides only. If, however, folded mountains are caused by contraction due to the cooling of the earth, the compression must take place from all sides. With the view of illustrating this, I requested the Cambridge Philosophical Instrument Company to make for me an apparatus consisting of four square beams of wood, resting upon a floor, which by means of screws could be moved nearer to, or farther from, each other. The beams left between them a space 2 feet across and 9 inches in depth. In this square central space 1 placed layers of cloth, baize, oil-cloth, cement, etc., separated by layers of sand. The machine was then set in motion, and compressed so that the central space was reduced from 24 inches square to 22. Since last year I have made other experiments, changing the arrangement in various ways. The results differ in details in almost every case, the initial movements being probably determined by slight differences in