366 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



15 per ton of lifting power, the former rate obtaining as regards 

 the more recently constructed docks. 



Painting and repairs cost about Sd. per ton per year of 

 lifting power. 



Taking the Barrow Floating Dock, with a lifting power of 

 3200 tons as an example, the average annual expenditure foi 

 wages is given as 450, equal to a cost of 2s. Wd. per ton of 

 lifting power, or about 1 per cent, on the first cost. 



The cost of coal, oil, cotton waste, etc., varies with the work 

 clone; but it is charged at the rate of 4d per ton of lifting 

 power, or about one-ninth per cent, on the first cost. 



The total yearly outlay on an average of years is equal to 

 4s. Id. per ton of lifting power. 1 



. d. 



Dams. Cost of Iron Caisson Coffer-dam used in the construction of the 

 Thames Embankment, including excavation, concrete inside, timber 

 shoring, and cost of removal 2 per foot run 30 7 5J 



Cost of the timber dams employed in the construction of the Thames 

 Embankment, between Waterloo Bridge and the eastern end 

 of the Temple Gardens, consisting of two rows of whole-timber 

 piles with clay filling, supported by whole-timber shores and 

 walings 3 per foot run 18 11 4 



Cost of removal per foot run 140 



19 15 4 



Cost of heavy timber and clay dam across the entrance of the Low- 

 water Basin, Birkenhead * per foot lineal 5G 



Timber and clay dam constructed across the Victoria Dock, Hull 5 



PIT foot lineal 21 



Coat of the Dublin Coffer-darn, including the front and back piling to 

 the foundation pit, extending to a depth below coping of from 43 

 to 46 feet, cross-dam struts and every charge connected with the 

 construction, maintenance, and removal 6 ... per foot lineal 15 



The timber dam constructed in the entrance of the Avonmoutli Lock 

 (Figs. 40, 41), consisting of horizontal whole-timber trusses and 

 shoring, and sheeted on the outside with 4-iuch vertical planking, 

 cost 1500, or about 9s. 9d. per foot super of dam on the face, or per 

 foot run of length of coping level 7 20 10 



Portsmouth Dams 8 *. d. 



Inner dam shallow part 8 10 



llfinoval 200 



Per foot run 10 10 



1 Engineering, vol. Hi. p. 4GO. * M.P.J.C.E., vol. liv. p. 18. 



1 Ibid., vol. xxxi. p. 25. 4 Hid., vol. H. p. 149. > Ibid., 150. 



Ibid., p. 159. 7 Ibid., vol. Iv. p. 21. 8 Ibid., vol. Ixiv. 



