6 26 Mr. mann’s 'Treat ife 
the other. The two round rods fixed at the ends of the 
boat, moving within thefe parallel cords, ferved to make 
the boat move in a right line in the middle of the canal, 
without running againft either fide, which it would have 
done without this precaution. The canal itfelf was upon 
an exact level, and One end of it, where the pulley was 
fixed, refted upon the fide of a well tw r enty-three feet 
deep, twenty of which were above the furface of the 
water; which gave fufficient fpace for the free and uni- 
form defcent of the lead-weight and cord running over 
the pulley, as they drew the boat from one end of the 
canal to the other. 
Latts, exadtly divided into inches, w r ere nailed againft 
each end of the canal within, to mark the diffei'ent 
depths of the water in it according as it fliould be aug- 
mented or diminilhed. The outfides of the little boat, 
from its keel upwards, were likewife divided into inches. 
In the infide of the boat was a quantity of fand fufficient 
to fink it to fix inches deep in the water. The common 
loaded bilanders in the Low' Countries ufually draw fix 
feet of water. 
\ t 
Thus the form of the wooden canal, together with its 
breadth and depth, and the form and dimenfions of the 
little boat, together with the depth of water it drew by 
means of its ballaft of fand, exactly correfponded with 
thofe 
