M. Girard on Navigable Canals. 123 
tablishment of the relation here assigned between the draft 
of water of the boats and the lift of the canal-locks. By aug- 
menting that draft of water, and by diminishing that lift, it 
will be possible to transport the same mney “of goods on 
narrower canals; the ground occupied by the canals will 
there aa be. less, and consequently cost less purchase 
money,” while the loss al water by evaporation will dimin- 
ish in the same proportio 
he manceuvreing of sh gates will be much easier, and 
may be confided to the boatmen, as is practised on the small 
canals in England, by which means the wages and lodgment 
of the Lock-keepers may be saved. 
The pressure of water on the sides and bottoms of the 
locks being much less will cause less dam and conse- 
quently render the repairs less Sedans: and costly. By 
this means roan navigation. will be no longer exposed to 
those frequent and long interruptions which have heretofore 
been necessary for the purpose of repairs. 
Finally, narrower boats with a greater draft of water, 
will offer less resistance when tracked,* and as they may 
be decked, their cargoes will be more secure than in ordi- 
nary flat-bottomed boats. 
Ina future mewn I shall develope n more fully the last 
1 which I have here. ig es out. In cau 
this, I shall only re remark that the disc ry of lock na 
by che" mancnavicing. 6 
fourteenth century, ‘ben artillery was ey SAC 
by n aking cannons to throw bat sh. eS two to 
ct, heir unwieldly 1 mass ‘soon compelled eee 
ot o pera ‘There now pate semen 
