310 M. P. S. Crirard/on Mivigable Canals. 



a distance of 6 Kilometres (3f miles) which occasions a 

 considerable annual expense. 



According to the most accurate information, the weight 

 of matter annually transported from Creuzot to the creek 

 is about four millions of Kilogrammes, or 4000 tons ; 

 while the weight of articles which ascend, and which con- 

 sist principally in soda to supply to glass-works, and in 

 castings from Tranche Comte, does not exceed 400 tons. 

 The weight of matter which descends from Creuzot into the 

 canal, is therefore, to the weight of matter which is carried 

 up to the establishment, as 10 is to 1. 



A navigable canal which should be established from 

 the mines and the foundery of Creuzot, would there- 

 fore require but a very small supply of water, if the 

 proper proportions were observed between the lift of the 

 locks and the draft of the boats destined to navigate the 

 canal. 



If, for example, the boats employed in this navigation 

 drew, when loaded, ItW metres, (4^ feet,) these boats 

 when returning would draw but 20 centimetres, (6| inch- 

 es) ; the difference of draft in the same boats when de- 

 scending with a full charge or returning with one tenth 

 part of a full load, would therefore be lyW metres. (3 feet 

 7| inches, nearly.) 



The whole descent throughout the length of this canal, 

 from Creuzot to the creek of Torcy, 6 Kilometres, is 48 

 metres (158 feet ;) so that giving to each lock a lift of one 

 metre (3jVo f'^^t, and supposing the passage of the boats to 

 be alternate, not only the expense of water from the upper 

 level would be null, but even a certain portion might be 

 made to flow into it from the creek of Torcy, where the 

 canal would terminate. 



It is easy to conceive that the locks for so small a lift 

 might be constructed at a small expense, and would be 

 much less liable to be injured by the pressure of water, 

 than though the lift were greater; for the pressure on the 

 works, and their consequent deterioration, is dependant on 

 the difference of level above and below the lock. 



If it be objected that the multiplicity of locks would re- 

 tard the navigation, without considering that it is here less 

 a question of economizing time than water, it is not difficult 

 to assure ourselves that this objection is without founda- 

 tion. . 



