JM. p. S. Girard on Jsavigahle Canals. 311 



We have already seen that the exportations from Creu- 

 zot, in pit coals and castings, amounted to 4000 tons per 

 annum ; let us now suppose that their transportation should 

 be effected in 200 days, this would be a movement of 20 

 tons per day ; let us suppose farther that boats of that ca- 

 pacity are employed, that is, of 20 tons burthen, these boats 

 will be about 14 metres (46 feet) long, lj%\ metres (4 [eet 

 11 inch.) wide, and will draw IfVo nuetres (4^ feet) of wa- 

 ter, including their weight. 



The fall of each lock being fixed at one metre it would be 

 necessary to draw from some other level 20 to 22 tons of 

 water to fill the basin of its descending lock. This water, 

 being introduced by orifices whose sum should be equal to 

 I of a square metre, (19| inches square.) we find, after ma- 

 king all necessary corrections, that to empty and fill the ba- 

 sin, it would not require quite a minute ; adding two other 

 minutes for lost time, we see that the passage of the boat 

 through 48 locks would require about two hours and an 

 half, allowing three hours for going the remaining length of 

 the canal, and the whole duration of the passage from the 

 lower pond of Creuzot to the creek of Torcy would be but 

 five hours and an half ; which would permit a boat to de- 

 scend and return in the shortest days of the year. 



This example suffices to shew how easy it would be by 

 establishing navigable canals, such as the one we have just 

 described, to increase the operations of extensive iron 

 works and coal-mines. The want of water cannot be an 

 obstacle to this establishment ; for, in the forges divers 

 parts of their machinery are generally moved by water, 

 and the water drawn from the coal mines would be sufficient 

 to supply such a canal. 



If, instead of being placed at the bottom of a gorge with- 

 out issue, as are the establishments of Creuzot, the coal 

 mines, the Iron Founderies, the Marble quarries, the for- 

 ests, (SiC. to be worked, were situated on a culminating 

 point between two vallies traversed by^ navigable rivers, the 

 canal which should unite these two rivers might be con- 

 structed according to our principles. 



The cumbersome articles taken, in this case, from the 

 culminating point of the canal must necessarily descend to 

 arrive at the point of consumption, and will never be re- 

 placed, at the place whence they are taken, by articles of 

 equal weight ; it is evident that, in vwtue ojf the excess of 



