MECHANICS AND USI FUL ARTS. 17 



from an already organized base of railways al honif ; the ma- 

 terial for the Indian lines had to be borne over thousands of miles 

 of a sea voyage. The construction of the Indian railways has 

 presented difficulties of a mu( h more formidable character than 

 those which have been met with on the Pacific line. It is true 

 that this railway has been carried over vast plains and mountain 

 ranges of which little was known, and in the face of the attacks 

 of hostile Indian tribes. In India, the works were carried out in 

 the face of difficulties connected with the oppressive heat of the 

 climate; through forests and jungles which were the resort of 

 savage animals, and the people employed were natives of the 

 country, speaking a language unknown to those by whom they 

 were employed, and whose habits and modes of life unfitted them 

 for labor such as that on which they were engaged. Great works 

 such as those of the Bhore Ghaut and ThuU Ghaut inclines pre- 

 sented difficulties equal to, if not greater, than any experienced 

 in the crossing over the Rocky Mountains. Streams wider and 

 more rapid than met with between Omaha and San Francisco 

 have been successfully bridged, and present some of the greatest 

 triumphs of modern engineering science. — Engineering. 



ON ROADS AND RAILWAYS IN NORTHERN INDIA AS AFFECTED 

 BY THE ABRADING AND TRANSPORTING POWER OF WATER. 



Mr. Login, at the meeting of the British Association, com- 

 menced by stating general conclusions he had arrived at, to the 

 effect that the abrading and transporting power of water was in- 

 creased directly as the velocity and inversely as the depth ; also, 

 that when flowing water had once got its proper load of solid 

 matter in suspension all erosive action ceased. In short, that it 

 was like a balance, the load being always equal to the power, 

 which power, somehow or other, increased as the velocity became 

 .gieater, and decreased as the depth of a stream increased, Nature 

 always adjusting the load to the various circumstances. He thea 



fave a short description of the plains and rivers of Northern 

 ndia, and, by the aid of diagrams, went on to argue that rivers 

 flowing through alluvial plains were raising rather than lowering 

 their beds, and, though this silting-up process may be very slow, 

 ye*^ it was satisfactory to the engineer to know that the founda- 

 tions of his bridges would be as safe, if not safer, a hundred 

 years hence, as they are now. In speaking of the changes of the 

 course of rivers, he said that there was more or less a constant 

 cutting going on, on the concave banks of a river, with atilting- 

 up process on the opposite side. The next subject referred to was 

 the denudation of the high level plains of Northern India called 

 "Doabs" (two waters), and locally known by the name of 

 "Bhanger^' land, in contradistinction to the term " Khadir," or 

 low valley lands, through which the large rivers, fed by the melt- 

 ing snows, now meander. Mr. Login said that the higher ridges, 

 or " back bones," of these Doabs were not caused by any up- 

 heavals, but were formed by the denudation of these high level 



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