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Page 23
We now come to George Stephenson, who did for the locomotive what Watt
did for our other steam-engines. His first engine had two vertical
cylinders of eight inches diameter and two-feet stroke, working by
cross-heads; the power was given off by spur-wheels; it had no springs,
consequently it jolted very much on the then bad railways; the wheels
were all smooth, as Stephenson was sure the adhesion would be
sufficient. It began work on the 25th July 1814, went up a gradient of
one in 450, and took eight waggons with 30 tons at four miles an hour.
It was by far the most successful engine that had yet been made. The
next and most valuable improvement of Stephenson was the blast-pipe--by
its means the slow combustion of the fire was at once overcome, and
steam obtained to any amount. This pipe was the result of careful
observation and great thought. His next engine had horizontal connecting
rods, and was the type of the present perfect machine. This truly great
man did not rest here, but time would fail, as well as your patience, if
I were to proceed further. Enough to say, that he afterwards established
a manufactory at Newcastle, and time has shown the result and benefit it
has proved to the whole world at large. A short time before the
Liverpool and Manchester Railway was opened, Stephenson was laughed at
because he said he thought he could go thirty miles an hour, and was
urged before the House of Commons not to say so, as he might be thought
to be mad. This I have from person who knew the circumstances.
Nevertheless, at the trial, I believe the "Rocket" did go at the rate of
thirty miles an hour, to the not small astonishment of the world, and
especially to the unbelievers in steam as a land agent. The stipulation
made was that trains were to be conveyed at the rate of twelve miles an
hour.
In our present perfect engines, the coke or fuel consumed per mile is
about 18 lbs. with a train of 100 tons gross weight, carrying 250
passengers. A first-class carriage weighs 6 tons 10 cwts.; a
second-class, 5 tons 10 cwts., each with passengers; a Pullman car
weighs about 30 tons. Our steamers consume 5 lbs. of coal per
horse-power in one hour. And last, not least, one of the greatest
improvements we have had in steam propulsion is the screw. Again, I may
also name the great advantage derived from steam by our farmers in
thrashing out grain. The engines principally used in farm-work are what
are termed high-pressure, or of the same class as the locomotive. The
great saving in cost in the first place, the simplicity and ease of
action in the second, and the small quantity of water required to keep
them in action, are all reasons why they should be preferred. The danger
in the one, that is, the high-pressure, over the condenser, is very
small, and all that is required is common care to guard against
accidents. Steam being a steady power, is much to be preferred to
water, as by its constant and uniform action the tear and wear of
machinery is much diminished, and of course proportionate saving made in
keeping up the mill or any other machinery.
Having now, to the best of my power, so far as a single lecture will
permit, brought the steam-engine from 120 B.C. to the present time, it
only remains for me to say, that it shows how actively the mind of man
has been permitted to work to bring it to perfection by the direction of
an all-wise Providence, "who knows our necessities before we ask, and
our ignorance in asking." A traveller by rail sees but little of the
vast and difficult character of the works over which he is carried with
such ease and comfort. Time is his great object. No age of the world has
conquered such difficulties as our engineers have had to deal with, and
the result is now before the eye of every thinking traveller. Our
engineers were at first self-taught, and many a self-taught man has had
reason to rejoice in the time he spent in his education. Of these men we
have examples in Brindley, who was at first a labourer and afterwards a
millwright; Telford was a stone-mason; Rennie a farmer's son apprenticed
to a millwright; and George Stephenson was a brakesman at a colliery.
Perseverance with genius, and a determination to overcome, made them the
great men they were. That you may so persevere and strive is the earnest
wish of him who has this evening had the great pleasure of giving you
this lecture, and who feels so greatly obliged to you for the very
patient hearing you have given him.
_ON ATTRACTION_.[B]
_Gravitation_.--Attraction, which may be illustrated by the effect a
magnet has on a piece of iron, may be viewed generally as an influence
which two bodies, say, exert on each other, under which, though at a
distance, they tend to move towards each other till they come into
contact. The force by which a body has weight, and, when free, falls to
the ground, is of this nature; and it is called, from _gravis_, "heavy,"
the gravitating force of the earth, because it causes weight, and
because, though emanating in a small degree from the falling body, it is
mainly exerted by the earth itself. It is under the action of gravity
that a pendulum oscillates: it is by that unseen influence it begins to
sway alternately downward and upward as soon as it is moved to a side;
and it is only because it is withheld by the rod that the ball or bob
keeps traversing the arc of a circle and does not fall straight to the
earth.
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