1916.] The Third Indian Science Congress. ] 



xxxui 



thus about |th only of their visible mass standing above sea-level. 

 The discovery of mountain compensation struck a blow at all 

 theories which attributed the elevation of mountains to any addi- 

 tional masses that had been pushed in from the sides. The eleva- 

 tion of mountains by subterranean lava squeezed in from the 

 side had to be rejected because it gave to mountains additional 

 mass; the wrinkling of the Earth's surface by lateral horizon- 

 tal forces had to be rejected because it gave to mountains 

 additional mass pushed in from the sides. As the Himalaya 

 possess only |th of their apparent visible mass, I am led to 

 suggest that the principal cause of their elevation has been the 

 vertical expansion of the rocks underlying them, vertical ex- 

 pansion due to physical or chemical change. The name of Pratt 

 and the name of Kaliana have now permanent places in the 

 history of science, and in this city of the United Provinces it 

 is only right that I should recall to you that the great theory 

 of mountain compensation, since found true in every continent, 

 had its origin in the United Provinces, and that its author 

 lies buried in these Provinces at Ghazipur. 



You will understand from this diagram that if the Earth's 

 interior shrinks and if the outer crust is squeezed up into 

 wrinkles like this, the mountains must possess much additional 



mass: the theory of compensation forbids such additional 

 mass. 



The contraction theory was gradually becoming discredited 

 under the attacks of Fisher, Dutton and others, and it 

 seemed some years ago to be moribund, when it was given a 

 fresh lease of life by the publication and translation into 

 several languages of Professor Suess's great work, The Face of 

 the Earth. This work is a critical history of all past geographi- 

 cal, geological and geodetic research; the wealth of its detail, 

 the courtesy of its criticisms have won for Suess' s work uni- 

 versal admiration. 



But from the geodetic point of view it is disappointing ; it 

 accepts the contraction theory in its entirety, and it rejects the 

 theory of Mountain Compensation. Suess does not obscure 

 the issue, as some writers do, by the indefinite adoption of con- 

 tradictory theories; being quite clear in his own mind he is 

 quite clear to his readers. He states that he does not believe 

 m the compensation of mountains by underlying deficiencies of 

 mass. Now the compensation theory has been found to be 

 true in India, Europe and America: nowhere do mountains 

 attract the plumb-fine as the law of gravitation would lead us 

 to expect. So you see that the geodesists are sharply opposed 

 to the school of Suess. Now what is Suess's reason for reject- 

 *ng the theory of mountain compensation? It is this: he 

 states quite clearly, "mountain compensation is inconsistent 

 with all geological observations." Whilst I admit that moun- 

 tain compensation is inconsistent with certain geological 



