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industrial biography-第25部分
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evidence on the trial of Neilson's patent in 1839; but the invention
does not appear to have been perfected by him。
。。。'
The construction of a bridge of iron was an entirely new idea。 An
attempt had indeed been made at Lyons; in France; to construct such a
bridge more than twenty years before; but it had entirely failed; and
a bridge of timber was erected instead。 It is not known whether the
Coalbrookdale masters had heard of that attempt; but; even if they
had; it could have been of no practical use to them。
Mr。 Pritchard; an architect of Shrewsbury; was first employed to
prepare a design of the intended structure; which is still preserved。
Although Mr。 Pritchard proposed to introduce cast…iron in the arch of
the bridge; which was to be of 120 feet span; it was only as a sort
of key; occupying but a few feet at the crown of the arch。 This
sparing use of cast iron indicates the timidity of the architect in
dealing with the new materialhis plan exhibiting a desire to effect
a compromise between the tried and the untried in
bridge…construction。 But the use of iron to so limited an extent; and
in such a part of the structure; was of more than questionable
utility; and if Mr。 Pritchard's plan had been adopted; the problem of
the iron bridge would still have remained unsolved。
The plan; however; after having been duly considered; was eventually
set aside; and another; with the entire arch of cast…iron; was
prepared under the superintendence of Abraham Darby; by Mr。 Thomas
Gregory; his foreman of pattem…makers。 This plan was adopted; and
arrangements were forthwith made for carrying it into effect。 The
abutments of the bridge were built in 1777…8; during which the
castings were made at the foundry; and the ironwork was successfully
erected in the course of three months。 The bridge was opened for
traffic in 1779; and proved a most serviceable structure。 In 1788 the
Society of Arts recognised Mr。 Darby's merit as its designer and
erector by presenting him with their gold medal; and the model of the
bridge is still to be seen in the collection of the Society。 Mr。
Robert Stephenson has said of the structure: 〃 If we consider that
the manipulation of cast…iron was then completely in its infancy; a
bridge of such dimensions was doubtless a bold as well as an original
undertaking; and the efficiency of the details is worthy of the
boldness of the conception。〃*
'footnote。。。
Encyclopaedia Britannica; 8th ed。 Art。 〃Iron Bridges。〃
。。。'
Mr。 Stephenson adds that from a defect in the construction the
abutments were thrust inwards at the approaches and the ribs
partially fractured。 We are; however; informed that this is a
mistake; though it does appear that the apprehension at one time
existed that such an accident might possibly occur。
To remedy the supposed defect; two small land arches were; in the
year 1800; substituted for the stone approach on the Broseley side of
the bridge。 While the work was in progress; Mr。 Telford; the
well…known engineer; carefully examined the bridge; and thus spoke of
its condition at the time: 〃The great improvement of erecting upon
a navigable river a bridge of cast…iron of one arch only was first
put in practice near Coalbrookdale。 The bridge was executed in 1777
by Mr。 Abraham Darby; and the ironwork is now quite as perfect as
when it was first put up。 Drawings of this bridge have long been
before the public; and have been much and justly admired。〃*
'footnote。。。
PLYMLEY; General View of the Agriculture of Shropshire。
。。。'
A Coalbrookdale correspondent; writing in May; 1862; informs us that
〃at the present time the bridge is undergoing repair; and; special
examination having been made; there is no appearance either that the
abutments have moved; or that the ribs have been broken in the centre
or are out of their proper right line。 There has; it is true; been a
strain on the land arches; and on the roadway plates; which; however;
the main arch has been able effectually to resist。〃
The bridge has now been in profitable daily use for upwards of eighty
years; and has during that time proved of the greatest convenience to
the population of the district。 So judicious was the selection of its
site; and so great its utility; that a thriving town of the name of
Ironbridge has grown up around it upon what; at the time of its
erection; was a nameless part of 〃the waste of the manor of Madeley。〃
And it is probable that the bridge will last for centuries to come。
Thus; also; was the use of iron as an important material in
bridge…building fairly initiated at Coalbrookdale by Abraham Darby;
as the use of iron rails was by Richard Reynolds。 We need scarcely
add that since the invention and extensive adoption of railway
locomotion; the employment of iron in various forms in railway and
bridge structures has rapidly increased; until iron has come to be
regarded as the very sheet…anchor of the railway engineer。
In the mean time the works at Coalbrookdale had become largely
extended。 In 1784; when the government of the day proposed to levy a
tax on pit…coal; Richard Reynolds strongly urged upon Mr。 Pitt; then
Chancellor of the Exchequer; as well as on Lord Gower; afterwards
Marquis of Stafford; the impolicy of such a tax。 To the latter he
represented that large capitals had been invested in the iron trade;
which was with difficulty carried on in the face of the competition
with Swedish and Russian iron。 At Coalbrookdale; sixteen 〃fire
engines;〃 as steam engines were first called; were then at work;
eight blast…furnaces and nine forges; besides the air furnaces and
mills at the foundry; which; with the levels; roads; and more than
twenty miles of iron railways; gave employment to a very large number
of people。 〃The advancement of the iron trade within these few
years;〃 said he; 〃has been prodigious。 It was thought; and justly;
that the making of pig…iron with pit coal was a great acquisition to
the country by saving the wood and supplying a material to
manufactures; the production of which; by the consumption of all the
wood the country produced; was formerly unequal to the demand; and
the nail trade; perhaps the most considerable of any one article of
manufactured iron; would have been lost to this country had it not
been found practicable to make nails of iron made with pit coal。 We
have now another process to attempt; and that is to make BAR IRON
with pit coal; and it is for that purpose we have made; or rather are
making; alterations at Donnington Wood; Ketley; and elsewhere; which
we expect to complete in the present year; but not at a less expense
than twenty thousand pounds; which will be lost to us; and gained by
nobody; if this tax is laid upon our coals。〃 He would not; however;
have it understood that he sought for any PROTECTION for the homemade
iron; notwithstanding the lower prices of the foreign article。 〃From
its most imperfect state as pig…iron;〃 he observed to Lord Sheffield;
〃to its highest finish in the regulating springs of a watch; we have
nothing to fear if the importation into each country should be
permitted without duty。〃 We need scarcely add that the subsequent
history of the iron trade abundantly justified these sagacious
anticipations of Richard Reynolds。
He was now far advanced in years。 His business had prospered; his
means were ample; and he sought retirement。 He did not desire to
possess great wealth; which in his opinion entailed such serious
responsibilities upon its possessor; and he held that the
accumulation of large property was more to be deprecated than
desired。 He therefore determined to give up his shares in the
ironworks at Ketley to his sons William and Joseph; who continued to
carry them on。 William was a man of eminent ability; well versed in
science; and an excellent mechanic。 He introduced great improvements
in the working of the coal and iron mines; employing new machinery
for the purpose; and availing himself with much ingenuity of the
discoveries then being made in the science of chemistry。 He was also
an inventor; having been the first to employ (in 1788) inclined
planes; consisting of parallel railways; to connect and work canals
of different levels;an invention erroneously attributed to Fulton;
but which the latter himself acknowledged to belong to William
Reynolds。 In the first chapter of his 'Treatise on Canal Navigation;'
published in 1796; Fulton says: 〃As local prejudices opposed the
Duke of Bridgewater's canal in the first instance; prejudices equally
strong as firmly adhered to the principle on which it was
constructed; and it was thought impossible to lead one through a
country; or to work it to any advantage; unless by locks and boats of
at least twenty…five tons; till the genius of Mr。 William Reynolds;
of Ketley; in Shropshire; stepped from the accustomed path;
constructed the first inclined plane; an
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