1 839.] On Wells used in Foundations in Upper India. 33 i 



might escape, especially where there is a head water with springs 

 opposed to it. In locks or descents, for instance, constructed in sand, 

 where the subsoil in addition to its own natural spring water has 

 that of the Canal to act upon the flooring of the lower chambers, there 

 is a considerable tendency to the removal of the sand under these 

 lower floorings, which seriously affects the stability of a work, and is 

 only to be provided against by enclosing all the subsoil in continuous 

 lines of foundation. I shall hereafter describe a remedy invented by 

 Col. John Colvin, C. B. of the Engineers, formerly Superintendent of 

 the Delhi, and Superintendent General of, Canals ; but in the mean- 

 time it is evident that where wells or cylinders are used, the continuity 

 of a wall is imperfect under any circumstances ; for place them as close 

 together as possible, there is still a separation — the curtain so much 

 desired is wanting. The methods adopted by me in the two cases, 

 first, where wells are sunk dose together, or leaving a space of six or 

 eight inches, which is the least that can be safely given, and, secondly, 

 when at a greater distance apart, are these — piles, and as the English 

 engineers now term it, concrete (an article which, I may observe in 

 passing, has been in use in Hindoostan from time immemorial) ; the 

 former in the works on the Doab Canal varying from sixteen to five 

 and a half feet in length, and the latter laid in as deeply as possible be- 

 tween the piles, and allowed to stand for some days to settle and in- 

 durate. The piles are made of young Saul trees ( Shorea robusta) cut in 

 the forests in the northern slope of the Sewalik hills, in the Deyra 

 Dhoon ; or when only five and a half feet long, of the species of rafter 

 called by the natives Kurri, the smaller sort averaging from ten to 

 twelve feet long and three and a half inches square, sawed out of Saul 

 timber in the forest, and imported in immense abundance into the 

 plains swung on the back of bullocks by the Brinjarris, or class of people 

 who lead a roving life, employing their cattle in this species of work. 

 The concrete consists of kunker, an alluvial lime rock peculiar to In- 

 dia — of stone boulders from the river broken into fragments — the gutta or 

 refuse of lime kilns, mixed with a proportion of cement, consisting of 

 two or three parts of soorkhee, or pounded brick, and one part of the 

 best stone lime thrown in and well mixed together with a pole, 

 sharp at one end and blunt at the other ; the former to stir up the 

 mixture for a certain time, and the latter to ram it down until it is 

 properly placed in position. 



The figures in plates 1 and 2 represent these methods in detail, 

 with the neemchuck and tools used by the well-sinkers ; and in plate 

 4, which is a plan and section of falls and locks as constructed on 

 the Doab Canal, the application of both will be easily recognized. 



x x 



