The Express.
London, England, 1851-05-17 00:00:00

LONDON, SATURDAY EVFYING, MAY 17, 1851.

this engine excelled them both), we should have
placed it in the front rank." From the above report it
as plain that for practical work in farming Garrett's
sane is the most suitable. The point on which the
jedges preferred the prize engines, Clayton's and
ornsby's, was that they consumed less coal, namely.
Clayton s, 7.771b5., and Ilornsby's 7.561b5., per horse
power per hour, while Garrett s consumed 11.291 b..
of coal per hour for each horse power. In getting
up the steam Clayton's engine consumed 431b5.,
Hornsby's 391b5., and Garretes 311bs. of coal.
We have entered somewhat fully into descrip-
tions of these important agricultural machines, be-
cause we hope that the attention of artisans and
others engaged in the construction or management
of machinery in manufactures may be induced to
examine and criticise this department of mechanical
skill, and may so suggest objections and defects
which may lead to improvement. At the same time,
the tests of practical husbandry are of more import-
ance than the mere tests of the trial yard; for it will
be found that many implements which never obtain
prizes are most extensively used by farmers, and
stand the test of every day use, where prize imple-
ments faiL And so sensible are manufacturers of the
necemity of constant practical trials of their imple-
ments, that some of them—as, for instance, Howard
of Bedford—actually occupy farms mainly for the
purpose of watching and trying their implements in
the ordinary farm work.

14TACTTryfrItY.

Since our last visit to this department of the
Exhibition an addition has been made to the
stock of locomotives. in the shape of a broad
gunge engine built by the Great Western Rail-
way Company. It presents nothing new in
point of construction : one of the main objects
attended to now-a-days by most of the locomotive
builders is to have nll the working ports secured to
the frame—that is, independent of the boiler ; this'
simplifies the construction to a certain extent. We
look upon it as a decided improvement, but it is one
which does not seem to be attended to by the com-
pany. The engine, when in working oder, weighs
37 tons; the tender, with water and coke, weighs
17 tuns 13 cwt. :making a total of 52 tons 13 ewt. : it
is capable of taking a passenger train of 120 tons at an
average speed of 60 miles per hour upon easy gradients.
We fear the working expenses will fall heavy.
The engine in all complete weighs .52 tons, and
the average weight of train it can take is 120 tons;
' now, if it actually takes a train of 101 tons, it will
be pretty well, and if we take the whole train with
engine complete, the engine alone will be one-third
the weight of the whole train ; that is, one-third of
the power required to move the whole train will be
absorbed by the engine alone. It must be considered
that the ballast on which the permanent way is laid
is to a certain extent elastic. In fact, elasticity is
an essential ingredient for the durability of railways;
I now, when a heavy weight is placed on the penua-
nent way, it must cause depression to a certain ex-
tent ; and the greater the weight is, of course, greater
! will the depression b.. This is another objection
to such heavy engines ; the engine is, as it nets, in a
continual hollow, which will absorb a certain con-
tinual amount of power.
We forgot to mention Nasmyth's steam hammer,
which forms a prominent feature, not only at the
Exhibition, but in all engine factories and iron-
works. It is wonderful, too, us a piece of mechanism.
and perhaps speaks more for the advance made of
late in the perfection of machinery titan oily modern
piece of mechanism. 'That a machine subject to such
avy concussions should lie at the same time capable
of the most perfect adjustment in action without
being liable to derangement is wonderful. The
hanuncr can not only be made to come down with the
combined action of gravity and the pressure of
steam, which will give the most violent blow it is
capable of producing, but it can be regulated with
sufficient nicety to crack a nut. In fact, we have
been in iron-works where we saw two steam-ham-
mers lying idle, simply because the men would not
allow tho hammers to fall with their full force on the
bloom. By regulating the hammer, they could bent up
the iron so as to look well,but when it came to be rolled
it was found to be full of dross, and they were
obliged to recur to the old tilt hammers. The prin-
ciple on which the hammer acts is simple enough :
the cylinder is above, the piston-rod passing through
a stuffing-box beneath is immediately connected to
the hammer; one of the difficulties which had to be

~..
overcome was how to connect the hammer to the
piston-rod, without communicating the serious con-
cussions of the hammer to the piston ; this was done
by packing the end of the piston-rod in the hammer
between pieces of wood, and keying it down, the
mama' was sufficiently elastic to prevent the concussions
effecting the piston : the action of the valve and regu-
lating apparatus is too complicated to ente into here.
The department devoted to machinery in motion,
which we now enter, will prove more attractive to
the general mass of v sitors than that we have just
left ; machinery when in motion has, as may be well
conceived, a more lively appearance, and excites
curiosity more than when at a stand-still, especially
of the general visitors of the Exhibition, who come
more from motives of curiosity than utility.
The first thing on entering which attracts atten
tion, arc waterfalls which cause a good deal of noise,
and fur that reason will, no doubt, prove attractive ;
one of them is exhibited by Mr. Appold; the water is
raised by what is commonly called centrifugal force.
This is done by giving a rapid rotatory motion, to a
kind of circular fan, which will be more easily under-
stood by looking at one, than by any attempt at de-
scription; it is really curious to witness the quantity
of water they will raise.
We believe that then are no engineers who, per-
haps, have done more towards bringing steam navi-
gation to perfection than Messrs. Maudslay's and
Yield; they exhibit a small double-cylinder direct-'
acting high pressure steam-engine of six horse power,
used 111 driving a coining press on a new principle,
a model of a new patent gun metal screw propeller,
and models of their different direct-action en-
gines for paddle-wheel steamer+, to all of
which we direct the attention of all lovers of machi-
nery. kiregards the six horse double-cylinder engine,
it is on the same principle as those built by Messrs.
Maqdslay's for large marine engines, except that
being a high pressure engine, it is divested of the
gear requisite fur working the air-pumps, &e. Direct
action engines, which only means that instead of
transmitting the motion through the medium of
beams ar side levers, it is transmitted direct, are gra-
dually superseding beam engines, because, first of
all, the fewer the parts through which motion is
transmitted the better. Beam engines also take up 1
more room ; in the case of direct-action engines, the
cylinders lying immediately under the crank shaft,
the diffiadty consists in obtaining room for the eon- ,I
fleeting rod to work, there being very little space I
between the top of the cylinders and the crank shaft.
Messrs. Maudslay's have patented different plane,
which all seem to have been attended with success. i
The case of this lime six-horse engine illustrates one I
of the plans; there arc two cylinders placed as I
close to each other as circumstances will allow, the
piston-rods are connected together by means of
what we eon only liken to a T, the tops of
the piston-rods are fixed to the ends of
the cross-piece, the tail end going down between two
cylinders, works in guides, the connecting rod being
forked• the forks pass down each side of the tail end,
thus the rod passes down from the crank to the bot-
tom of this tail end, on which it vibrates. The plan
is simple enough in this ease, but when it has to
work air-pumps, &c., when applied to maainc engines,
of which there is a model, it has a much more com-
plicated appearance. The chief feature about the
, coining press is, that instead of producing the pres-
sure by a screw or lever, it is produced by an eccen-
tric. We could not see exactly how the eccentric
acts, being hidden; at each stroke of the press, that
is after the coin has been stamped, a little arm Shoots
forward which carries a blank coin along with it,
knee t he coin which has been stamped off the die,
and co the blank one in its stead; it then re. 1
tarns, e press comes down, produces the inspres- 1

lion, and the operation of placing another coin in
its stead is repeated. The whole is ilea and compact.
The feathering screw is an ingenious invention.
One of the advantages derived from the screw pro-
pelling system is that with a fair wind the screw can
be unshipped and the vessel can proceed in every re-
spect like a sailing vessel, having no impediment;
the plan adopted for unshipping tho screw has
hitherto been a tedious process, the propeller being
lifted out of the water by two screws working in
guides ; in the patent feathering screw the two fans
arc brought into one plane by a simply piece of me-
chanism, and are secured in a lino with the rudder,
so that they offer no obstruction whatever to the pro-
' greasy of the vessel when under sale. A few years
since we saw a feathering screw, but it was to ascer-
tain which was the best angle the fans should be
placed at for propelling, we don't know whether this
screw of Maudalay's is intended to do that, at all
events it is a pretty invention, though it remains to
be seen how it will answer in practice.
There is a huge connecting-rod adapted to marine
steam engines, of the collective power of eight hun-
dred horses; this connecting rod is made to work an
engine of four hundred horses power; it is a beauti-
ful piece of workmanship. The brasses are lined
inside with patent metal, a substance getting much
into use for bearings, &c., it is found to work smoother
and does not require so much oil as brass.
We now come to a set of beautiful models, illus-
trating the different kinds of merino engines in ge-
nital nse for paddle wheel steamers. The first is
pair of double-cylinder engines• built on the same
plan as that wliklt is ut work, except that it has all
the requisite appurtenances for condensing. which
gives it a very complicated appearance. There arc also
a pair of vibrating engines on the same principle as
those exhibited by Penn, of twenty-four horse k)ower.
A model of a patent double piton-rod engine, is
another plan for obtaining direct action ; iu this ease
the centre of the cylinder is plums under the shalt ;
there was no possibility, therefore, to form a con-
nexion between a piston rod working in the centre
of the cylinder and the crank, because the crank is
so low that it only just clears the top of the cylinder.
Het-our:4e was had, therefore to two piston rods,
which allowed the crank to work between them.
Their action was combined above, from which a 0111-
meting rod working in guides came down and
worked the crank. We believe they worked well ;
but the connecting rods, guides, &e., have to he above
deck. Next is a model of a beam engine, which the
other plans are intended to supersede, and which no
doubt they do ; hut still one must not be blind to
the merits of these old engines : all the heavy parts
lie low at the bottom of the vessel, and the beams on
each side are convenient for working the pumps.
The chief fault lies in there not being direct action.
The last model is a pair of annular cylinders,
another plan for obtaining direct action. In this
case the cylinders stand also plumb under the
crank shaft; but the cylinders arc annular, that is,
a tube passes down the centre of each cylinder, in
which the tsomecting rod vibrates. The pistons are
of courseannular. and there arc two piston rods to
each, which are connected together, and work the
connecting rods just the same way as in the double
cylinder engines. Altogether the engine has a very
simple and compact appearance. (Inc thing alone
puzzles us, that is, how the the inner part of the an-
nular piston is kept steam tight. There must be
some affinity between these engines and Penn's
trunk engines, though Mandalay may not have
taken his idea from the latter.

In pursuing our investigations amongst the ma-
chinery, we may remark that our chief object has
been to point out the most modem improvements
which have been successful in practice, the success of
machinery in practice lying the best criterion of its
utility. We have remarked on a previous occasion,
that there is nothing here very new or wonderful.
The more we investigate the mechanical department
of the Exhibiti:m, the more confident do we feel in
stating that the mechanical genius of the country
is far from being perfectly nresented. The
generality of our great engineers, whatever
be the 'branch of engineering they have ulti-
mately followed, have risen from humble
ranks, and have attained eminence in life, simply
through their mechanical genius. There is plenty,
perhaps a superabundance, of mechanical genius to
this country, but very little of it is to be seen in the
Exhibition, because. perhaps, the class in which it is
most developed had not the means of so exhibiting ;
and the same want of means is the reason why a
great number of inventions do not come before the
public. On an ociasion like this, the humbler classes
of mechanics of this country ought to have been in-
vited to exhibit under more auspicious circumstances.
The French would not have so large a show, but for
the generosity of its government.

W. G. Armstrong exhibits models of some of his
hydraulic machinery, us applied to cranes, corn lifts,
and a machine for washipping coals. Here the pres-
sure of the water is obtained by a small steam engine
forcing water into what is technically termed
the accumulator, where the water acquires a
certain pressure. When the crane is re-
quired to act, the water is allowed to press
on a piston in a cylinder, and as the piston moves
from one end of the cylinder to the other, a chain
being attached to the end of the piston rod 'wows
over a series of rallies, by which the stroke of the
piston is multiplied; the chain then passes over the
jib of the crane, and being secured to the object re-
quired to be raised, the hoisting is thus performed.
By causing the chain to pass through a system of
pulleys, the stroke of the piston can be multiplied to
any length, the pressure of water iv also made sub-
servient to swinging the crane. The application of
this principle may do very well where the pressure
of water can be readily obtained, but when it comes
to having a steam engine, for the purpose of forcing
water into an accumulator, we doubt such a system
coming into extensive practice. First of all it is me-
dial effect, that is transmitting power through a
medium, which is a plan we like to see
avoided as much as possible, because a certain
amount of power must be lost in the transmission.
The atmospheric principle as adapted to railways, is
lan instance of medial ctfect, namely, pumping air
by means of steam-engines, although air is by no
means such a favourable medium to deal with as
water. It mast be allowed that the system of pump-
ing water presents some advantages, such as being
easily stored up and ready for use at any time, but
we believe that where steam power has to be em-
ployed, the more direct that power is the better.

Cunningham and Carter exhibit their new system
of propulsion on railways; it is on the atmospheric
principle; we have not heard of its having been
tried in practice, and don't supposo we ever will.
In fact, the moro we find inventors deviate from the
first principle of atmospheric propulsion, which every
one ought to know has been tried practically—we
allude to the plan of a continuous tube, in which a
piston works, which being immediately connected
to the train, is forced along by atmospheric pressure
—the more inventors deviate from this mode, the less
likelihood has there been of their plans succeeding.
The present system consists in having small station-
ary engines placed along the line at short distances
apart ; these engines are worked by atmospheric
pressure (which is medial effect), the driving wheels
are on each side of the rails, and lie horizontally ;
they are so placed that when a train passes between I
them, the wheels will press upon rails placed on each
side of the train ; these engines set to work imme-
diately the train comes up to them, and, of course,
these wheels send them along. Let us screw up suffi-
cient imagination to suppose one of these trains to be
going at the rate of forty miles an hour, which is by
no means an extraordinary speed, and as the train
passes one of these engines with the wheels buzzing
round, let us ask ourselves, is the engine driving
the train aor is the train driving the engine-
we certainly would be impressed with the belief
that the latter action was taking place; it is absurd to
suppose that an engine aria be started and can give
out power in so short a space of time. Then,
sup-
I
posing such a system to be m actual practice, every
Lima the train plumed one of these engthes the per-