69S CAN 
out of the cradle will make no difference to the balance; 
for, when theboat with its freight enters the cradle, it dii- 
places as much water as its own weight; and, when the boat 
leaves the cradle, as much water fucceeds as keeps the ma¬ 
chine in equilibrium. At the end of each canal that goi- 
refponds with the land wherein the machinery is erected, 
mud be gates or doors, fuch as would be necelfary to com¬ 
municate with a common lock ; w ith this difference only, 
the gates or doors of the lower canal need not be higher 
than the water in the low er canal, and to open the contrary 
way. As one end of the cradle wili correfpond with the 
gates of the lower canal, when lowered to the fame plane, 
the framing of the doors or gates of fuch lower canal muff 
be made to fit the correfpcnding end of the cradle, and 
jointed fo exaftly that, when covered with leather, or 
wadding of oakum, and drawn forcibly together by dogs 
or fcrew bolts, no water may be loft. The fame muff be 
obferved of the framing of the gates or doors of the upper 
canal, and which muff be made to fit the correfponding end 
of the cradle, when the cradle is drawn up to the fame 
plane with the upper canal, in all refpefts as the other be¬ 
fore-mentioned. When the commercial boat is intended to 
be conveyed from the canal to the cradle, the cradle is to 
be bolted or (crewed to the framing of the doors of the 
canal, and then the door or hide of the cradle drawn up or 
..opened, and the doors of the canal opened; the boat is 
then free to float into the cradle. Then the doors and Hides 
of the canal and cradle being flint, and the bolts drawn 
back or unfcrewed, the cradle is prepared for afcending or 
defcending, according to its refpeftive fituation. It may be 
worked by a rack and pinions ; or with a capftan with 
ropes, &c. A frame muff be made from the bottom of the 
well to the height of the upper canal, on both Tides of the 
machinery, for the wdiole to Aide up and down it with free¬ 
dom and exaftnefs ; and with rollers at the fides and ends 
of the cradle and diving cheft, to prevent any great degree 
of friflion. It would caufe the machinery to move with 
greater exaftnefs, if, on the fides and near each corner on 
the top of the framing, there was a large pulley for a rope 
to pafs over; one end of which rope fliould be fattened to 
th.e cradle, and at the other end a weight fufpended. The 
weights may be of any magnitude that may Be found con¬ 
venient to regulate the machinery; for inftance, fuppofe 
four, two on each fide, of one ton weight each, then the di¬ 
ving cheft may be made proportionally lefs, the weight an¬ 
swering the fame purpofeasthe vacuity in the diving cheft, 
and the whole load that refts upon the pillars may be ba¬ 
lanced by weight alone, and do without the diving cheft 
and pillars, if in any particular fituation it (hould be found 
difficult to make a well with fecurity. In our models we 
find only this difference, that the balancing by weight is a 
.caufe of greater friftion, and will Require a framing fo 
much the ftronger in proportion to the number and mag¬ 
nitude of the weights employed, and alfo a capftan fuch 
that a horfe may be applied to ; in order to work the ma¬ 
chinery,‘the weights may be connefted to the crjdles either 
by ropesor chains. It muft beobferved, that the machinery, 
when erefted with the diving cheft and prepared for de¬ 
fcending, that the pillars, whether of iron or wood, as they 
defcend into the water, lofe, if of'iron, fome of their abfo- 
lute gravity, if of wood, the whole. In order to regulate 
the difference that will be caufedby the pillars defcending 
in w ater, it will be neceflary to have a conical barrel, with 
a weight and rope proportionate, to regulate the differencee; 
the weight to be fo applied as to afllft in forcing down the 
cradle, in proportion as the pillars lofe of their gravity. The 
machine, whether with weights or a diving,cheft for a ba¬ 
lance, will, aft with the fame uniformity with refpett to the 
cradle that receives the commercial veil'd, and will make 
fio other difference but the quantity of friftion, in one cafe 
more than the other. Farther, if a commercial boat he 
.empty, or but half laden, it will make no difference to the 
machinery aiding, as a portion of water will always remain 
in the cradle, proportionate to the levity of the commercial 
yeffel and its freight. The machine with the diving cheft 
A L. 
may, in fome Situations, be applied with advantage to the 
ule of water-engines lor mines or manufacturing of iron, 
cotton, &c.” 
How far thefe feveral methods may be found to anfwes 
the purpofes intended, nothing but experience, and un¬ 
prejudiced trials, can determine. In the mean while Mr. 
James 'FufTell, of Mells, in Somerfetfhire, feems to have 
provided againft their failure, by the invention of a ba¬ 
lance-lock for raifing and deprefling boats on navigable ca¬ 
nals, by a very Simple operation ; and for which he ob¬ 
tained a patent, dated December 24, 179S. He deferibes 
his invention as follows: “ I the faid James FufTell do 
declare, that my invention is deferibed in manner follow¬ 
ing ; that is to fay : the nature and method of my invention 
is by a perpendicular lift, by a balance-lock or machine, 
with wheels, chains, ferews, veflels or receptacles, levers, 
fhafts, and rack-wheels, of a particular conftruftion, as 
hereinafter deferibed. Firft, fuppofe a particular rife or 
fall, as, for inftance, from about forty to fifty feet, which 
is about equal to the rife or fall of fix or eight common 
locks, and which I propofe to overcome without lofs of 
water. 1 o conftruft; which, your canal fliould be brought 
to a quick or fteep defeent of a hill ; and, if the lift in¬ 
tended is not above forty or fifty feet, this lock may be 
built open at the end next to the lower level, with two fide 
walls, and one end wall, to the upper level, and alfo a par¬ 
tition wall, to divide the faid lock into two equal parts, 
which may be called lock-pits. But, if requifite or conve¬ 
nient to have a very deep lift, for inftance, 100 feet or more, 
it will be neceflary to wall the lock-pits both fides and ends, 
and to have a (I1011 tunnel from the lower level to the bot¬ 
tom ot the lock-pits ; the lock-pits muft be built long and 
wide enough for th.e receptacles, which are intended to 
convey the boats or barges up or down from one level to 
another, (which receptacles muft be two in number, and 
made exaftly of the fame dimenfions,) with a partition 
wall or framing in the middle, of the fame thicknefs as the 
width of the aperture or lock-pit, and built either of brick, 
ftone, or timber. On this partition is to be placed or fixed 
a (haft, of fufficient ftrength ; upon each end of which a 
wheel is to be fixed, of greater diameter, by two or more 
inches, than the thicknefs of the faid wall or partition ; fo 
that the chain which works over the wheels, (hall hang 
or work clear of the partition wall, in defcending or af¬ 
cending. Now the receptacles are two open boxes or cif- 
terns, of fufficient length, and fuitable to receive the boats 
or barges intended for the trade, about fix feet width in. 
fide, and from three to fix feet deep, made of wood, iron, 
or any other metal, fo as to be made water-tight; under 
each of thefe receptacles is fixed a very ftrong framing of 
oak-timber, fecured with braces and bolts of iron, &c. 
and of dimenfions and ftrength fit to fupport two wheels, 
of equal diameter with thofeon the fhaft above deferibed, 
and placed at fimilar diftances. Upon each corner of the 
upper parts of the receptacles, and alfo at the lower cor¬ 
ners of th.e framing, are placed fmall iron wheels or roll¬ 
ers, which run in grooves of iron, fixed upon timbers placed 
in the wall for that purpofe, which guide the-receptacles, 
and keep them horizontal. To regulate the motion, and 
fix it in any pofition, there is a tooth-wheel fixed on one of 
the wheels of the fhaft aforefaid, which works into a pinion 
fixed on a fmall fhaft or fpindle, with a fly and break 
wheel thereon. Now the two receptacles and frames un¬ 
derneath muft be made exaftly of the fame dimenfions, in 
every refpeft, fo as to balance each other; and, as they 
are to be filled with water of an equal depth, will be of 
equal weights ; and, in order to preferve a balance on the 
woiks, it will be neceflary to fix a balance-chain to the 
bottom of each receptacle, of equal weight, per foot or 
yard, with the chain that works the machine, w hich will 
alternately counterpoife each, in afcending or defcending. 
Now there are two chains made of wrought or caft iron, or 
of other metal, of fufficient length, according to the 
height of the fall, and of ftrength more than adequate 
to the weight to be raifed or let down. Thefe chains 
are 
