884 
possible way diminish the vibrations and strains to 
which it was subject, and which would otherwise ra- 
pidly wear out the machinery. For this purpose he 
proposed to connect the engine with its carriage by 
means of steam acting on six pistons in lieu of springs. 
But perhaps his most material improvement con- 
sisted in the very simple one of throwing the waste 
The steam- high-pressure steam as a blast into the chimney, 
blast. which was found to increase enormously the force of 
the fire, and the evaporating power of the boiler.’ 
Engines having this improvement, and with two ver- 
tical cylinders, as constructed in 1818, are, or were 
lately (1854), still atwork on the Killingworth railway 
dragging coals at the rate of five or six miles an hour. 
(397.) One of Stephenson’s clear practical opinions was 
Rejects the this,—that the locomotive and the railway are part 
steam-car- of one mechanism, and must be adapted to one an- 
riage on 
roads. other. He was not a friend to steam-carriages on 
common roads, and the event proved his sagacity, 
(398.) If the idea of a locomotive belongs to no one man, 
Origin of still less does that of a railway, which being one of 
railways. the most elementary of mechanical contrivances, 
may be traced, under some modifications, almost inde- 
finitely backwards, as a means of conveying heavy 
loads with facility. Hence it was at first confined 
chiefly to quarries and collieries, especially in under- 
ground passages or drifts. The gauge of these sub- 
terranean railways, or tram ways, was only about 18 
inches, The material of the rails was first wood, then 
cast iron, finally wrought iron, as being less liable 
to wear and to accident. The wrought iron rail, 
though not absolutely new, was first generally intro- 
duced in 1820. About the same time, or rather 
sooner, the rails began to be made plain, that is, 
without any vertical guide or flange to prevent the 
wheels of the carriages from leaving the rail, and the 
flange was transferred to the wheels of the locomo- 
tive. Even this was not new, for it had been used 
by Jessop in 1789. The weight of the rails has 
been constantly on the increase. The original cast- 
iron rails weighed only 15 lb. a yard ; the malleable- 
iron rail in 1821 weighed about 28 Ib., then 35, 
afterwards 64, and now rails of 80 Ib.,a yard are 
generally used. , 
(399.) One of Stephenson’s first cares was to make his 
Stephenson railways solid and level, and to prevent jerks at the 
adapts | thedunction of the rails. The gauge he adopted, or the 
locomotive. interval between the rails (now generally used, except 
on the Great Western Railway and its branches), was 
4 ft. 8} inches, and was derived from the accidental 
width of the parent railways in Northumberland. 
Like Watt and all other innovators, his great diffi- 
culty was to get the machinery of his locomotives pro- 
perly made, and the great railway movement of 1825 
was anticipated by the establishment in 1820 of 
an engine factory at Newcastle, which, till after the 
MATHEMATICAL AND PHYSICAL SCIENCE. 
[Diss. VI. 
opening of the Liverpool and Manchester Railway in 
1831, remained the only one, and for long afterwards 
the best of its class. The cranked axle contrived by 
Trevithick, and abandoned because it could not be 
properly welded, was now restored ; the heavy loco- 
motive was placed on strong but easy steel springs, 
wrought iron was skilfully introduced into the wheels 
of the carriages, and the whole machinery was made 
to work with precision, and to combine a degree of 
resistance never before anticipated with comparative 
lightness. The factory was established in 1821, and 
the first passenger locomotive was started on the Dar- 
lington and Stockton Railway in 1825. 
I ought, perhaps, to apologize for these details, 
but they illustrate so well the exceedingly gradual 
progress of mechanical invention, that I have thought 
them worthy of mention here.! The subsequent his- 
tory of the locomotive and the railway is more gene- 
rally known. From the date of 1825, both grew and 
flourished; the railway first and most steadily; the 
locomotive was introduced more cautiously, and met 
with much opposition ; its triumph was almost en- 
tirely due to the steadiness of George Stephenson. 
The year 1825, so fertile in speculation, produced 401.) 
a series of projects for railways to an extent not com- Railway 
monly known, since few of them came into existence SPecule- 
or were even commenced for many years later. The1gg5, 
projected capital of these companies amounted to not 
less than L..30,000,000 or L.40;000,000. But the 
only considerable undertaking which was at that time 
seriously supported was the railway from Liverpool 
to Manchester, and on that battle-field were fought 
the great questions of the superiority of railways to ‘ 
common roads,—of high to low velocities of trans- 
port,—and of locomotives to fixed engines. 
On these three important points,GeorgeStephenson 402.) 
was in advance both of the science and of the prac- Superiority 
tice of his age; and, accordingly, backed chiefly byte 
commercial men, who had entire confidence in his roads, 
sagacity, he had to maintain the conflict almost single- 
handed against general and professional prejudice. 
With respect to the Railway, he had long decided in 
his own mind against the use of steam-carriages on 
common roads, This conclusion was scientifically 
based on his own experiments on the friction of wag- 
(400.) 
gons on railways made in conjunction with Mr Ni- 
cholas Wood, civil engineer at Newcastle, as far back 
as the years 1815 and 1816. A simple dynamometer Stephen- 
of Stephenson’s invention was used, and by means ofs0n's expe- 
it the two fundamental propositions were established, pager 
that the friction is directly as the pressure, and that ito¢ trains, 
is quite independentof velocity (at leastwhen the speed 
was moderate). It may be said that these proposi- 
tions were already known; but, besides that probably 
Stephenson and Wood were equally unacquainted 
with the writings of Coulomb, they could not have 
1 I have found many curious details of the early history.of railways in a series of articles on the life of George Stephenson 
in the Civil Engineer Journal for 1848 and 1849, Iam indebted to Mr Robert Stephenson, M.P., for many interesting parti- 
culars respecting his father’s inventions. 
di 
