The British Press; or, Morning Literary Advertiser.
London, England, 1825-01-06 00:00:00

XII.

Published this day in rat 3r0., prim Os.
The MODERN ATHENS: a Dissecuon awl Demonstration
of Man and Things in the Scotch Capital.
)Y • MODEUX 0111111.
_ _ _

This day are published, price tra, or Proof Plates on India Paper,
price js.
ILLUSTRATIONS to )100RE'S IRISH
141E1A/DIES. Consisting of Seven Plates, including a Vignette
Title Page to bind with the volume,. exquisitely cngrartd on atce
from Resigns by Richard Weltsll, kaq.,

RAIL-WAYS.
In calculations respecting the power of a horse exerted
in different modes, errors often arise from considering this
power as a constant quantity, which it is not. At a dead
pull an ordinary horse exerts a force of traction equal to
150 pounds ; this is reduced to less than one-half when he
travels four miles an hour; to one-ninth part when he
travels eight miles an hour; and at twelve miles an hour
his whole strength is expended in carrying forward his
own body, and his power of traction ceases. It is sa
here that the horse performs pretty long journeys. P;1111:6n.
travelling very short stages, he may exert a force consider-
ably greater, and his power of traction may perhaps cease
only at a velocity of 13 or 16 miles an hour. Hut in com-
mon cases a velocity of 12 miles may be taken as the max-
imum ; and, for the convenience of calculation, the dead
pull may be taken st 144 pounds. Adopting then, Pro-
fessor Leslie's rule, the force of traction at any degree of
velocity (a) will be=(l2—v)2. Thus, the force exerted.
at two miles an hour, will be 100 potnds ; at four
64 pounds • at six miles, 36 pounds ; at eight miles, 1u
pounds; and at ten miles, only four pounds. Steam-engine
makers assume a horse-power to be equal to a weight of
180 or 200 pounds, but this is to be considered merely as
an arbitrary and conventional standard, adopted for a par-
ticular purpose. It is necessary to keep this general con-
clusion in view, when we speak of the application of
horse-power to the traction of loaded waggons and vessels.
The resistance to the motion of a vessel in the sea or a
canal, is of an extremely different kind from that which
a carriage of any kind experiences upon a common road or
railway. In the former case it arises from the pressure ct
the water on the bow and sides of the vessel ; in the la to
from the friction of the axle in its box, and that of the rm.
of the wheel on the gravel or iron rail. The motion of
the body in both cases is resisted also by the air ; but tbis
resistance, which is small in amount, generally speaking,
we shall throw entirely out of view in the first instance,
order to simplify our calculations.
On a well-made road a horse will draw a load of 1 ton,
in a cart weighing 7 cwt., at the rate of two miles an hour.
(Leslie's Elements, p. 233). The whole strenvb of the
horse is exerted in overcoming the friction. On such a
road, therefore, a forge of traction of 100 pounds moves a
weight of 3,000 pounds, or the friction is 140th part of
the load (the cart included).
On a railway of the best construction, it has been shown
In a former paper that a horse, travelling at the same
rate of two miles an hour, draws 15 tons, including the
vehicles. In this case, then, a power of traction of 1141
pounds moves a weight of 33,600 pounds: the friction, cf
course, is 1.336 th part, or, in round numbers, 1-300th part
of the load.

On a canal, a horse travelling at two miles an hour draws
SO tons, in a boat weighing probab'y IS tons.• Redwine
the ton to 2000 pounds, for the sake of round numbers, as
in the last calculation, we find here that a power of tractiw.i
of 100 pounds moves a mass of 90,000 pounds, or the re-
sistance which the water opposes to the motion of the
vessel is equal to 1-900th part of the load or entire weight.
At sea, where the water-way is of unlimited breadth, the
resistance is probably one-third less ; but, as a compensa-
tion for this, when steam power is employed, there is pro-
bably a loss of one-third, in consequence of the disadvan-:
tageous mode of its application.
We see, then, that the effect produced by the draught
of a single horse is ten times es great upon a railway, and
thirty times as great upon a canal as ripen a well-made
road. Yet a railway costs only about three times as touch
as a good turnpike rosdt, and a canal about nine er ten
times: and the expense of keeping the railway and camel
in repair is probably less in proportion to the original cut-
lay than in the case of a road. It is ohi ions, then, that
were railways to come into general use, two-thirds,
more of the expense of transporting commodities would
saved.

With regard to the comparative advantages of cum's
and railways, so far as the present fa:ta go, we may
otr-
serve, that if a horse power effects three times as much
upon a canal ar upon a rail-way, the canal costs about
three times as much, and will, of course, require nearly Use
same rates or dues per tun to make the capital yiebl she
same interest.
• Boats in some eases carry only 15 or 20 tons ; in others 36 (as
the coal boats on the Union Canal); but in the one ease they tam.
yel quicker, and in the others slower, than the rate mentioned.
t In Mr. Telford's estimates for
.portions of new road between
Edinburgh and %V °oiler, we tird the expense to be from 1000:.
110 W. per mile, including the price of the grounds.

Ma. WIWITZI/I.—This veteran of the stage 'had on
Saturday last, at his lodgings in Wild-court, Drury-lane.
When the boy who attended him came with his breakti-t,
he was leaning on his hand, quite dead, and frcm the
calmness of his countenance, it may be hoped that he ex.
pired without pain. Ile was far advanced in We, and for
some years suffered the infirmities generally attendant on
eoch a period. In the prime of his days he was an excel
lent actor, particularly in French and Jewish character,'
Mr. NVewitzer possessed literary talents, but the labcurs
his profession, while he was able to continue on the stage,
and his infirmities after he left it, prevented him affording
them due cultivation. Ile was full of anecdote, portico.
laxly of the theatrical kind ; and his chief, if not his wily
subsistence, for many years, wag derived from one of thoae
admirable institutions, the Theatrical Wends.