84 C. BAILLAIEGÉ ON A PARTICULAE CASE OF 



to take its course towards the city by passing through the coudiiit under the bed of the 

 river. And this shows the importance and wisdom of duplicate mains at such points, and 

 in general throughout the whole line of any aqiieduct under considerable head, and, at 

 any rate, along the lower portions of it, as we haA^e already had several bursts in the main 

 at different points along the low levels between Lorette and Quebec, similarly caused by 

 a water-hammer induced by the gates being shut too rapidly in the hurry occasioned by 

 a conflagration in the city or by some other cause. 



In the present case the pipe, through 140 feet of its length, or between the points 

 at which it was to some extent confined in position by the temporary end-partitions of the 

 wooden tube or enclosure, had been bodily raised at the centre, I can not say how much 

 more, but at least six inches : for it was sunk to that depth in the iron chairs and wooden 

 bolsters, on which it reposed on the flooring of the tube. The pipe now forms in plan an 

 elongated S, or something in the shape of the figure, ACDB, in the cut, the breadth of the 

 tube or wooden enclosure (« b c d) being eight feet, its length (AB) 140 feet. At C the 

 flange of the faucet penetrated nine inches into the side of the tube, breaking through 

 the thre-inch deal lining; while at D the flange of the pipe at that point entered only 

 about one inch and a half. The side or lateral thrust was therefore eight feet, ten inches 

 and a half, and would, of course, have been much greater, had not the side walls of the 

 tube and the outer twelve-inch frame or truss work been there to iirevent portions of the 

 conduit at C and D from flying off into the river, which it is evident would have 

 happened, if unconfined in the way they were. 



The joints at C and D, as will be inferred from the angular deflection at each of these 

 points and the shortening of the conduit by so much, were completely detached and 

 separated ; the inner portion of the two pipes, forming the angle, being still the one within 

 the other, while, at the side nearest to the bridge-enclosure, the edge of the spigot was fully 

 three or more inches out and clear of the faucet in each case. At D, the leaden ring was com- 

 pletely out of the joint and lying on the flooring of the tube ; while at C, the lead was only 

 partly deranged. The faucet joints, where shown in the sketch, by short lines drawn 

 across the line, ACDB, representing the axial line of the pipe, were but slightly deranged 

 towards the ends, A and B, or loosened, say, to the extent of a sixteenth of an inch, while 

 the other joints were more and more loosened as they approached C and D. The portion 

 of the pipe between C and D, some thirty-two feet in length, remains perfectly straight, 

 turning as it did on or about the centre of its length on a pivot at the point 0, which 

 is about three feet from the centre of the tube, A B. 



Now, as to the force exerted in producing this effect on the pipe, this force must of 

 course be, at least, equal to the whole weight of the cast-iron conduit moved and of the 

 water which filled it before the accident. This combined weight is calculated at 51,406 

 lbs., so that this is evidently the lowest estimate of the buckling effort of the hydraulic- 

 ram or hammer, since the pipe and the water contained covTld not have been lifted clear 

 out of its supporting cradles, as it has been, by a less weight than its own. But that the 

 force or lifting weight exerted must have been much greater than this is evident from the 



