($8 
weight has been moved or lifted in a 
given time; but by leaving out of the 
ealculation the weight of a man, the 
measure becomes far more simple, and 
equally accurate for the purpose in view. 
To complete, however, the above calcu- 
lation, so as to indicate the mechanical 
power exerted by each manon the tread- 
wheel, we have to multiply his weight, 
which maybe taken at. the usual 
average of 150\bs. by 2000, the number 
of feet that weight has passed over in the 
hour, which gives 300,000 ; this number 
being multiplied by 63 the length of time 
that rate of action has been maintained 
for the day, the result is found to be 
2,000,000Ibs. raised one foot, as the 
- mechanical measure of daily exertion. 
The diameter of the tread-wheel does 
not form any part of the above calcula- 
tion. The meehanical power of course 
depends upon the diameter of a wheel ; 
but, as great power is not the leading ob- 
ject in the erection of these machines, it 
is found that the most convenient sizes 
for tread-wheels are from four to six 
feet diameter; and the height of the 
steps from seven to eight. inches, 
Wheels of larger diameter occasion 
increased expense, and occupy greater 
space in the prison. “Ibere might, how- 
ever, be some advantage in having one 
or more of the wheels in tke prison of 
different diameters, as. they would 
afford the means of varying the rate of 
exertion to a class, when occasion might 
require if. 
To the principle of hard labour, 
(says Sir John Cox. Hippisley in_his 
recent publication on this snbject,) as 
fairly intended by the Statute, so 
far from being an enemy, he is a 
most zealous friend ; but, during a con- 
siderable portion of a long-protracted 
life, having been much occupied in the 
duties of the provincial magistraey in the 
eounties of his usual residenee ; and 
having for many years, as a Visiting jus- 
tice, given an especial attention to the 
most considerable House of Correction 
in the county of Somerset, he has 
viewed, with more than an ordinary in- 
terest, the extreme to which this reac- 
tion in the public feeling has led ; and, 
particalarly, the popularity it has given 
to the very expensive* and enormous 
machinery of the tread-wheel; which he 
* The expense inenrred at Cold Bath 
Fields, eluding such alterations of the 
prison for the reception of the machinery 
as was, by Mr. Cubitt, deemed advisable, 
bas exceeded 12,0001, There is, as yct, no 
Proceeding's of Public Societies. 
[Aug.T,. 
has found from his own repeated investi- 
gations, and those of many enlightened 
and intelligent friends who have-en- 
gaged in the same inquiry, to be highly 
mischievous in its principle, and baneful 
in its effects, to those who are so 
indiscriminately sentenced to it; and, 
consequently, .an instrument which 
neither the government nor the people 
of this country can countenance, when 
its evils are fully laid before them. 
But, desirous of ascertaining the pre- 
sent state of the tread-wheel machinery 
in the East-India wareliouses, Sir J. C. 
Hippisley availed himself ofthe obliging 
intervention of a friend who bad re- 
cently presided in the chair of the East 
India Company, and who procured a 
minute report, drawn np by the principal 
oflicers of the warchouse departmest 
upon all the points of enquiry. The 
chicf officer of the Bengal warehouse 
states, that—‘‘of the five cranes, one 
was erected in that warehouse, and is 
still in use—the part of the warehouse 
which it serves not being provided with 
any otlier crane ;”’—but a note is sub- 
joined, announcing, “ that Edward Doe 
had his leg broken by working at this 
crane, and that Joseph Eames. also 
received a seyere injury in the Jeg from 
working at the same crane, which inca- 
pacitated him. fiom labour for some 
wecks ; and were relieved by the East 
mill-work of any sort attached to it; and, 
if mills and the necessary buildings be 
added, it is estimated that the additional 
expenditure will scarcely fall short of a 
moiety of the sum already expended. Fa 
a Treatise on Mechanics by Dr. Olinthus 
Gregory, (Professor of Mechanics in the 
Royal Military Academy of Woolwich,) 
will be found a description, accompanied 
with plates, of a tread-wheel in every 
respect analogous to that introduced by 
Mr. Cubitt, for which Dr. Gregory states 
that My. David Hardie, of the East India 
Company’s Bengal warehouse, obtained a 
patent. But Mr. Hardie himself, in point 
of fact, had no pretension to the discovery 
of the principle, it being no other than 
that of a wheel long used by the Chivese 
in the irrigation of their plantations. Mr. 
Hardie’s machinery was applied to a 
crane instead of a mill, and is described by 
Dr. Gregory,—“ as a wheel, on the outside 
of which are placed twenty-four steps for 
the men to tread upon, at a situation 
where the steps are found at a_height 
equal to that of the axis, or where the 
plane of the steps became horizontal.” 
Five cranes of this description have, ac- 
cording to Dr. Gregory, been at work at 
the Zast India warehouses, and Mr, Har= 
die’s patent was obtained in 1803. 
India 
