116 M. Girard on Navigable Canals. 
pov The economy of water did not enter at all into 
the calculation which produced this change ; although this 
ould have been the most powerful motive had the expense 
of seater at the locks been submitted toa rigorous analysis. 
‘he most celebrated Engineers of France and England 
here continued to contribute to the sneintANING of ancient 
practices in this species of constructio 
We read in a memoir of Mr. Parca on the canal of 
Burgundy, that the greater or less space occupied by a boat 
in the lock of a canal, has no influence on the quantity of 
water expended for ihe passage, either in ascending or de- 
_ scending, and that there is therefore no reason for diminish- 
ing the lift of the locks, which, he says, is generally eight, 
ten or twelve feet. 
This opinion, advanced by an engineer so justly renowned, 
has never been contradicted; and if we may be permitted 
te judge from the canals which have been constructed since, 
has been contionally: sdmitiead without discussion or @X- 
amination 
This. trus that Mr. Gauthey, in “the meuncigs above cited, 
epmnarks tliat th e locks of a canal which has a summit level, 
should not be of equal lift, that the smallest lifts should be 
nearest the summit level, and that their height may be aug 
mented as the facility of supplying the expense by feeders 
increase. But Mr. Gauthey has not formally distinguished 
what precise circumstances, nor under what. restrictions 
die variation may take place; and although his idea indi- 
cates some notion of the existence of a certain relation be- 
tween the lift of the locks and the quantity of water required 
their service, he did not turn his attention to. the =e 
be yaar of that preiarians 
“dem filled. 
Ket us now establish the cathe wilh Sonik serve us 
¥ a! bonds Ueda ee 
