322 C R 1 
The goods being fattened to the crane, and raifed off the 
Boor of the warehoufe ready for letting down, the man 
puts the worm into gear, leaves the wheel, and lets the 
goods down by the winch. Provided it can conveniently 
be done, it would be advifable to throw the wheel in 
which the man walks out of gear, when the winch is 
made ufe of; this, however, would not be a matter of 
abfoiute necettity.” 
It is a well-known though melancholy faff, that num¬ 
bers of unfortunate perfons have loft their lives in the 
walking-wheel cranes, by their canting back, when over¬ 
powered by the weight craning up ; for the men having 
no means whereby to fave themfelves, their dellrmSlion 
is inevitable. The improvement fuggefted above is 
therefore highly deferving attention, inafmuch as it gives 
the workman a power of (topping the wheel at his plea¬ 
sure. But for this purpofe another contrivance has been 
lately invented by Mr. Jofeph Dixon of London, by 
adding to the crane a pair of what he calls prefervative 
wheels. Thefe he fixes to the axis of the walking-wheel; 
over which pafs two ropes, fufpending a bar of wood, 
for the men to lay hold of when overpowered, and by 
which they may fufpend themfelves, with the greatett: 
Safety, till all danger is paft. Thefe preservative wheels 
may be eafily affixed to any crane already erefted. The 
Society for the encouragement of arts, voted Mr. Dixon 
a premium for this invention. 
A crane worked by the powers of a double capftan, 
has alfo been lately conftru&ed by Mr. John Millington, 
of Golden-fquare, which he calls the double capjlan crane. 
This appears capable of raifing or letting down any 
weight; and being worked by the lever on pulleys, is 
attended with no danger, and entirely fuperfedes the ne- 
ceffity of the walking-wheel. 
But the mod perfect machine of this kind hitherto 
conftru&ed, appears to be that lately prefented to the 
Society for the encouragement of arts and manufactures, 
by Mr. James White, of Chevening, in Kent; and for 
which he was adjudged a premium of forty guineas. The 
properties of this crane, of which a figure is annexed, 
are as follow: i. Itis Simplicity, confiding of a mere wheel 
and axle. 2. Its only friction, exclufive of the pulleys, 
is that on the two gudgeons of the fhaft; and one ot 
thefe fupports the weight of the wheel, and of the man 
that works it, nearly in the direction of its point. 3. It 
is durable, as is evident from the two properties above- 
mentioned. 4. It is fafe ; for it cannot move but during 
the pleafure of the man, and while he is actually prefling 
on the gripe-lever. 5. This crane admits of an almoit 
infinite variety of different powers, and this variation is 
obtained without the lead alteration of any part of the 
machine. If, in unloading a veffel, there fliould be found 
goods of every weight, from a few hundreds to a ton, and 
upwards, the man that does the work will be able fo to 
adapt his ftrength to each, as to raife it in a fpace of 
time proportionate to its weight; he walking always 
with the fame velocity as nature and his greatett eafe 
may teach him. 
It is a great difad vantage in fome cranes, the annihi¬ 
lation of which has juftly become an objeCt of attention, 
that the fmalleft weight mutt be as long in railing as the 
largeft, unlefs the man turn or walk with a greater velo¬ 
city, which tires him in a ftill greater proportion. In 
other cranes, perhaps, two or three different powers may 
be procured ; to obtain which, fome pinion mutt be 
fhifted, or frefh handle applied, or reforted to. In this 
crane, on the contrary, if the labourer find his load fo 
heavy as to permit him to afcend the wheel without its 
turning, let him only move a ftep or two toward the 
circumference, and he will be fully equal to the tafk. 
Again, if the load be fo light as fcarcely to relift the 
action of his feet, and thus to oblige him to run through 
fo much fpace as to tire him beyond n.eceffity, let him 
move laterally towards the center, and he will foon 
feel the place where his ftrength will fuller the lealt 
N E. 
fatigue by raifing the load in queftion. It has been be¬ 
fore obferved that, if left alone, this crane will naturally 
reduce itfelf to a (late of reft, even though a weight 
were fufpended to it. The means will appear to be, the 
gripe or brake at the top, and its lever, which frretches 
acrofs the diameter of the wheel at the height of a man’s 
bread, when in an attitude of treading the wheel to the 
bed advantage. 
It may be neceffary to obfcrve, with refpeCt to the 
dimenfions of the prefent crane, and fome other pecu¬ 
liarities of its confirmation, that what is now the frame, 
and feems to form a part of the crane, mu ft be conlidered 
as a part of the building in which it is placed ; fince it 
would be moftly unneceffary, fhou’.d thefe cranes be ereCl- 
ed in houfes already built. With refpeCt to the horizon¬ 
tal part, by walking on which the man who attends the 
gib occaftonally affifls in raifing the load, it is not an ef- 
fential part of this invention, where the crane is not im¬ 
mediately contiguous to the gib, although, where it is, 
it would be certainly very convenient and economical. 
In warehoufes, and where this lhould be found unnecef¬ 
fary, together with the frame-work above alluded to, 
this crane would be extremely limple and cheap ; and 
this wheel, though of confiderable diameter, occupies 
but little room, from its thinnefs and inclination. A flit 
in a floor, about two feet wide, with a fupport above and 
below, for the axis, is all that is neceffary to conftitute and 
contain the crane ; for, goods may be flowed both under 
the whole wheel, and above nearly half of it, and there 
would be ample room to How a large quantity of goods 
properly fhelteredfrom the weather. Hence alfo it appears, 
that the houfe would diminifh the wharf-room much lels 
than many others, by (landing on lefs ground. One man’s 
weight alone, applied at the extremity of the wheel, would 
raife upwards of a ton ; and it need not be added, that a 
fingle-lheaved block would double that power. Suffice 
it to fay, that the fize may be varied in any required 
ratio; and that this wheel will give as great advantage, 
at any point of its plane, as a common walking-wheel of 
equal diameter, becaufe the inclination can be varied af 
pleafure, as far as expediency may require. Thefe re¬ 
marks will be more obvious by infpedling the figure ; 
wherein A reprefents a circular inclined plane, moving- 
on a pivot underneath it, and carrying round with it the 
axis 
