The Life of Thomas Telford by Smiles

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The other great aqueduct on the Ellesmere Canal, named Pont-Cysylltau,
is of even greater dimensions, and a far more striking object in
the landscape. Sir Walter Scott spoke of it to Southey as "the
most impressive work of art he had ever seen." It is situated about
four miles to the north of Chirk, at the crossing of the Dee, in
the romantic vale of Llangollen. The north bank of the river is
very abrupt; but on the south side the acclivity is more gradual.
The lowest part of the valley in which the river runs is 127 feet
beneath the water-level of the canal; and it became a question with
the engineer whether the valley was to be crossed, as originally
intended, by locking down one side and up the other--which would
have involved seven or eight locks on each side--or by carrying it
directly across by means of an aqueduct.

The execution of the proposed locks would have been very costly,
and the working of them in carrying on the navigation would
necessarily have involved a great waste of water, which was a
serious objection, inasmuch as the supply was estimated to be no
more than sufficient to provide for the unavoidable lockage and
leakage of the summit level. Hence Telford was strongly in favour
of an aqueduct; but, as we have already seen in the case of that at
Chirk, the height of the work was such as to render it impracticable
to construct it in the usual manner, upon masonry piers and arches
of sufficient breadth and strength to afford room for a puddled
water-way, which would have been extremely hazardous as well as
expensive. He was therefore under the necessity of contriving some
more safe and economical method of procedure; and he again resorted
to the practice which he had adopted in the construction of the
Chirk Aqueduct, but on a much larger scale.

[Image] Pont-Cyslltau--Side view of Cast Iron Trough

It will be understood that many years elapsed between the period at
which Telford was appointed engineer to the Ellesmere Canal and the
designing of these gigantic works. He had in the meantime been
carefully gathering experience from a variety of similar
undertakings on which he was employed, and bringing his
observations of the strength of materials and the different forms
of construction to bear upon the plans under his consideration for
the great aqueducts of Chirk and Pont-Cysylltau. In 1795 he was
appointed engineer to the Shrewsbury Canal, which extends from that
town to the collieries and ironworks in the neighbourhood of
Wrekin, crossing the rivers Roden and Tern, and Ketley Brook, after
which it joins the Dorrington and Shropshire Canals. Writing to his
Eskdale friend, Telford said : "Although this canal is only
eighteen miles long, yet there are many important works in its
course--several locks, a tunnel about half a mile long, and two
aqueducts. For the most considerable of these last, I have just
recommended an aqueduct of iron. It has been approved, and will be
executed under my direction, upon a principle entirely new, and
which I am endeavouring to establish with regard to the application
of iron."*[4]

It was the same principle which he applied to the great aqueducts
of the Ellesmere Canal now under consideration. He had a model made
of part of the proposed aqueduct for Pont-Cysylltau, showing the
piers, ribs, towing-path, and side railing, with a cast iron trough
for the canal. The model being approved, the design was completed;
the ironwork was ordered for the summit, and the masonry of the
piers then proceeded. The foundation-stone was laid on the 25th
July, 1795, by Richard Myddelton, Esq., of Chirk Castle, M.P., and
the work was not finished until the year 1803,--thus occupying a
period of nearly eight years in construction.

The aqueduct is approached on the south side by an embankment 1500
feet in length, extending from the level of the water-way in the
canal until its perpendicular height at the "tip" is 97 feet;
thence it is carried to the opposite side of the valley, over the
river Dee, upon piers supporting nineteen arches, extending to the
length of 1007 feet. The height of the piers above low water in the
river is 121 feet. The lower part of each was built solid for 70
feet, all above being hollow, for the purpose of saving masonry as
well as ensuring good workmanship. The outer walls of the hollow
portion are only two feet thick, with cross inner walls. As each
stone was exposed to inspection, and as both Telford and his
confidential foreman, Matthew Davidson,*[5] kept a vigilant eye
upon the work, scamping was rendered impossible, and a first-rate
piece of masonry was the result.

[Image] Pont-Cyslltau Aqueduct

Upon the top of the masonry was set the cast iron trough for the
canal, with its towing-path and side-rails, all accurately fitted
and bolted together, forming a completely water-tight canal, with a
water-way of 11 feet 10 inches, of which the towing-path, standing
upon iron pillars rising from the bed of the canal, occupied 4 feet
8 inches, leaving a space of 7 feet 2 inches for the boat.*[6]
The whole cost of this part of the canal was 47,018L., which was
considered by Telford a moderate sum compared with what it must
have cost if executed after the ordinary manner. The aqueduct was
formally opened for traffic in 1805. "And thus," said Telford, "has
been added a striking feature to the beautiful vale of Llangollen,
where formerly was the fastness of Owen Glendower, but which, now
cleared of its entangled woods, contains a useful line of
intercourse between England and Ireland; and the water drawn from
the once sacred Devon furnishes the means of distributing
prosperity over the adjacent land of the Saxons."

[Image] Section of Top of Pont-Cyslltau Aqueduct.

It is scarcely necessary to refer to the other works upon this
canal, some of which were of considerable magnitude, though they
may now seem dwarfed by comparison with the works of recent
engineers, Thus, there were two difficult tunnels cut through hard
rock, under the rugged ground which separates the valleys of the
Dee and the Ceriog. One of these is 500 and the other 200 yards in
length. To ensure a supply of water for the summit of the canal,
the lake called Bala Pool was dammed up by a regulating weir, and
by its means the water was drawn off at Llandisilio when required
for the purposes of the navigation; the navigable feeder being six
miles long, carried along the bank of the Llangollen valley.
All these works were skilfully executed; and when the undertaking
was finished, Mr. Telford may be said to have fairly established
his reputation as an engineer of first rate ability.

We now return to Telford's personal history during this important
period of his career. He had long promised himself a visit to his
dear Eskdale, and the many friends he had left there; but more
especially to see his infirm mother, who had descended far into the
vale of years, and longed to see her son once more before she died.
He had taken constant care that she should want for nothing.
She formed the burden of many of his letters to Andrew Little.
"Your kindness in visiting and paying so much attention to her,"
said he, "is doing me the greatest favour which you could possibly
confer upon me." He sent his friend frequent sums of money, which
he requested him to lay out in providing sundry little comforts for
his mother, who seems to have carried her spirit of independence so
far as to have expressed reluctance to accept money even from her
own son. "I must request," said he, "that you will purchase and
send up what things may be likely to be wanted, either for her or
the person who may be with her, as her habits of economy will
prevent her from getting plenty of everything, especially as she
thinks that I have to pay for it, which really hurts me more than
anything else."*[7] Though anxious to pay his intended visit, he
was so occupied with one urgent matter of business and another that
he feared it would be November before he could set out. He had to
prepare a general statement as to the navigation affairs for a
meeting of the committee; he must attend the approaching Salop
quarter sessions, and after that a general meeting of the Canal
Company; so that his visit must be postponed for yet another month.
"Indeed," said he, "I am rather distressed at the thoughts of
running down to see a kind parent in the last stage of decay, on
whom I can only bestow an affectionate look, and then leave her:
her mind will not be much consoled by this parting, and the
impression left upon mine will be more lasting; than pleasant."*[8]

He did, however, contrive to run down to Eskdale in the following
November. His mother was alive, but that was all. After doing what
he could for her comfort, and providing that all her little wants
were properly attended to, he hastened back to his responsible
duties in connection with the Ellesmere Canal. When at Langholm,
he called upon his former friends to recount with them the incidents
of their youth. He was declared to be the same "canty" fellow as
ever, and, though he had risen greatly in the world, he was "not a
bit set up." He found one of his old fellow workmen, Frank Beattie,
become the principal innkeeper of the place. "What have you made of
your mell and chisels?" asked Telford. "Oh!" replied Beattie,
"they are all dispersed--perhaps lost." "I have taken better care
of mine," said Telford; "I have them all locked up in a room at
Shrewsbury, as well as my old working clothes and leather apron:
you know one can never tell what may happen."

He was surprised, as most people are who visit the scenes of their
youth after a long absence, to see into what small dimensions
Langholm had shrunk. That High Street, which before had seemed so
big, and that frowning gaol and court-house in the Market Place,
were now comparatively paltry to eyes that had been familiar with
Shrewsbury, Portsmouth, and London. But he was charmed, as ever,
with the sight of the heather hills and the narrow winding valley--

"Where deep and low the hamlets lie
Beneath their little patch of sky,
And little lot of stars."

On his return southward, he was again delighted by the sight of old
Gilnockie Castle and the surrounding scenery. As he afterwards
wrote to his friend Little, "Broomholm was in all his glory."
Probably one of the results of this visit was the revision of the
poem of 'Eskdale,' which he undertook in the course of the
following spring, putting in some fresh touches and adding many new
lines, whereby the effect of the whole was considerably improved.
He had the poem printed privately, merely for distribution amongst
friends; being careful," as he said, that "no copies should be
smuggled and sold."

Later in the year we find him, on his way to London on business,
sparing a day or two for the purpose of visiting the Duke of
Buckingham's palace and treasures of art at Stowe; afterwards
writing out an eight-page description of it for the perusal of his
friends at Langholm. At another time, when engaged upon the viaduct
at Pont-Cysylltau, he snatched a few day's leisure to run through
North Wales, of which he afterwards gave a glowing account to his
correspondent. He passed by Cader Idris, Snowdon, and Penmaen Mawr.
"Parts of the country we passed through," he says, "very much
resemble the lofty green hills and woody vales of Eskdale. In other
parts the magnificent boldness of the mountains, the torrents,
lakes, and waterfalls, give a special character to the scenery,
unlike everything of the kind I had before seen. The vale of
Llanrwst is peculiarly beautiful and fertile. In this vale is the
celebrated bridge of Inigo Jones; but what is a much more
delightful circumstance, the inhabitants of the vale are the most
beautiful race of people I have ever beheld; and I am much
astonished that this never seems to have struck the Welsh tourists.
The vale of Llangollen is very fine, and not the least interesting
object in it, I can assure you, is Davidson's famous aqueduct
[Pont-Cysylltau], which is already reckoned among the wonders of
Wales. Your old acquaintance thinks nothing of having three or
four carriages at his door at a time."*[9] It seems that, besides
attending to the construction of the works, Telford had to
organise the conduct of the navigation at those points at which the
canal was open for traffic. By the middle of 1797 he states that
twenty miles were in working condition, along which coal and lime
were conveyed in considerable quantifies, to the profit of the
Company and the benefit of the public; the price of these articles
having already in some places been reduced twenty-five, and in
others as much as fifty, per cent. "The canal affairs," he says in
one of his letters, "have required a good deal of exertion, though
we are on the whole doing well. But, besides carrying on the
works, it is now necessary to bestow considerable attention on the
creating and guiding of a trade upon those portions which are
executed. This involves various considerations, and many
contending and sometimes clashing interests. In short, it is the
working of a great machine: in the first place, to draw money out
of the pockets of a numerous proprietary to make an expensive
canal, and then to make the money return into their pockets by the
creation of a business upon that canal." But, as if all this
business were not enough, he was occupied at the same time in
writing a book upon the subject of Mills. In the year 1796 he had
undertaken to draw up a paper on this topic for the Board of
Agriculture, and by degrees it had grown into a large quarto
volume, illustrated by upwards of thirty plates. He was also
reading extensively in his few leisure moments; and among the solid
works which he perused we find him mentioning Robertson's
'Disquisitions on Ancient India,' Stewart's 'Philosophy of the
Human Mind,' and Alison's 'Principles of Taste.' As a relief from
these graver studies, he seems, above all things, to have taken
peculiar pleasure" In occasionally throwing off a bit of
poetry. Thus, when laid up at an hotel in Chester by a blow on his
leg, which disabled him for some weeks, he employed part of his
time in writing his 'Verses on hearing of the Death of Robert
Burns.' On another occasion, when on his way to London, and
detained for a night at Stratford-on-Avon, he occupied the evening
at his inn in composing some stanzas, entitled 'An Address to the
River Avon.' And when on his way back to Shrewsbury, while resting
for the night at Bridgenorth, he amused himself with revising and
copying out the verses for the perusal of Andrew Little.
"There are worse employments," he said,"when one has an hour to
spare from business;" and he asked his friend's opinion of the
composition. It seems to have been no more favourable than the
verses deserved; for, in his next letter, Telford says, "I think
your observation respecting the verses to the Avon are correct.
It is but seldom I have time to versify; but it is to me something
like what a fiddle is to others, I apply to it in order to relieve
my mind, after being much fatigued with close attention to
business."

It is very pleasant to see the engineer relaxing himself in this
way, and submitting cheerfully to unfavourable criticism, which is
so trying to even the best of tempers. The time, however, thus
taken from his regular work was not loss, but gain. Taking the
character of his occupation into account, it was probably the best
kind of relaxation he could have indulged in. With his head full of
bridges and viaducts, he thus kept his heart open to the influences
of beauty in life and nature; and, at all events, the writing of
verses, indifferent though they might have been, proved of this
value to him--that it cultivated in him the art of writing better
prose.

Footnotes for Chapter VI.

*[1] The Ellesmere Canal now pays about 4 per cent. dividend.

*[2] 'A General History of Inland Navigation, Foreign and
Domestic,' &c. By J. Phillips. Fourth edition. London, 1803.

*[3] [Image] Section of Pier

Telford himself thus modestly describes the merit of this original
contrivance: "Previously to this time such canal aqueducts had been
uniformly made to retain the water necessary for navigation by
means of puddled earth retained by masonry; and in order to obtain
sufficient breadth for this superstructure, the masonry of the
piers, abutments, and arches was of massive strength; and after all
this expense, and every imaginable precaution, the frosts, by
swelling the moist puddle, frequently created fissures, which burst
the masonry, and suffered the water to escape--nay, sometimes
actually threw down the aqueducts; instances of this kind having
occurred even in the works of the justly celebrated Brindley.
It was evident that the increased pressure of the puddled earth was
the chief cause of such failures: I therefore had recourse to the
following scheme in order to a void using it. The spandrels of the
stone arches were constructed with longitudinal walls, instead of
being filled in with earth (as at Kirkcudbright Bridge), and across
these the canal bottom was formed by cast iron plates at each side,
infixed in square stone masonry. These bottom plates had flanches
on their edges, and were secured by nuts and screws at every
juncture. The sides of the canal were made water-proof by ashlar
masonry, backed with hard burnt bricks laid in Parker's cement, on
the outside of which was rubble stone work, like the rest of the
aqueduct. The towing path had a thin bed of clay under the gravel,
and its outer edge was protected by an iron railing. The width of
the water-way is 11 feet; of the masonry on each side, 5 feet 6
inches; and the depth of the water in the canal, 5 feet. By this
mode of construction the quantity of masonry is much diminished,
and the iron bottom plate forms a continuous tie, preventing the
side-walls from separation by lateral pressure of the contained
water."--'Life of Telford,' p. 40.

*[4] Letter to Mr. Andrew Little, Langholm, dated Shrewsbury,
13th March, 1795.

*[5] Matthew Davidson had been Telford's fellow workman at Langholm,
and was reckoned an excellent mason. He died at Inverness,
where he had a situation on the Caledonian Canal.

*[6] Mr. Hughes, C.E., in his 'Memoir of William Jessop,' published
in 'Weale's Quarterly Papers on Engineering,' points out the bold
and original idea here adopted, of constructing a water-tight
trough of cast iron, in which the water of the canal was to be
carried over the valleys, instead of an immense puddled trough,
in accordance with the practice until that time in use; and he adds,
"the immense importance of this improvement on the old practice is
apt to be lost sight of at the present day by those who overlook
the enormous size and strength of masonry which would have been
required to support a puddled channel at the height of 120 feet."
Mr. Hughes, however, claims for Mr. Jessop the merit of having
suggested the employment of iron, though, in our opinion, without
sufficient reason.

Mr. Jessop was, no doubt, consulted by Mr. Telford on the subject;
but the whole details of the design, as well as the suggestion of
the use of iron (as admitted by Mr. Hughes himself), and the
execution of the entire works, rested with the acting engineer.
This is borne out by the report published by the Company
immediately after the formal opening of the Canal in 1805, in which
they state: "Having now detailed the particulars relative to the
Canal, and the circumstances of the concern, the committee, in
concluding their report, think it but justice due to Mr. Telford to
state that the works have been planned with great skill and
science, and executed with much economy and stability, doing him,
as well as those employed by him, infinite credit. (Signed)
Bridgewater."

*[7] Letter to Mr. Andrew Little, Langholm, dated Shrewsbury,
16th Sept., 1794.

*[8] lbid.

*[9] Letter to Mr. Andrew Little, Langholm, dated Salop, 20th Aug.,
1797.

CHAPTER VII.

IRON AND AND OTHER BRIDGES.

Shrewsbury being situated in the immediate neighbourhood of the
Black Country, of which coal and iron are the principal products,
Telford's attention was naturally directed, at a very early period,
to the employment of cast iron in bridge-building. The strength as
well as lightness of a bridge of this material, compared with one
of stone and lime, is of great moment where headway is ofimportance,
or the difficulties of defective foundations have to be encountered.
The metal can be moulded in such precise forms and so accurately
fitted together as to give to the arching the greatest possible
rigidity; while it defies the destructive influences of time and
atmospheric corrosion with nearly as much certainty as stone itself.

The Italians and French, who took the lead in engineering down almost
to the end of last century, early detected the value of this material,
and made several attempts to introduce it in bridge-building;
but their efforts proved unsuccessful, chiefly because of the
inability of the early founders to cast large masses of iron,
and also because the metal was then more expensive than either stone
or timber. The first actual attempt to build a cast iron bridge was
made at Lyons in 1755, and it proceeded so far that one of the
arches was put together in the builder's yard; but the project was
abandoned as too costly, and timber was eventually used.

It was reserved for English manufacturers to triumph over the
difficulties which had baffled the foreign iron-founders. Shortly
after the above ineffectual attempt had been made, the construction
of a bridge over the Severn near Broseley formed the subject of
discussion among the adjoining owners. There had been a great
increase in the coal, iron, brick, and pottery trades of the
neighbourhood; and the old ferry between the opposite banks of the
river was found altogether inadequate for the accommodation of the
traffic. The necessity for a bridge had long been felt, and the
project of constructing one was actively taken up in 1776 by
Mr. Abraham Darby, the principal owner of the extensive iron works
at Coalbrookdale. Mr. Pritchard, a Shrewsbury architect, prepared
the design of a stone bridge of one arch, in which he proposed to
introduce a key-stone of cast iron, occupying only a few feet at
the crown of the arch. This plan was, however, given up as
unsuitable; and another, with the entire arch of cast iron, was
designed under the superintendence of Mr. Darby. The castings were
made in the works at Coalbrookdale, and the bridge was erected at a
point where the banks were of considerable height on both sides of
the river. It was opened for traffic in 1779, and continues a most
serviceable structure to this day, giving the name to the town of
Ironbridge, which has sprung up in its immediate vicinity. The
bridge consists of one semicircular arch, of 100 feet span, each of
the great ribs consisting of two pieces only. 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."*[1]

[Image] The first Iron Bridge, Coalbrookdale.

It is a curious circumstance that the next projector of an iron
bridge--and that of a very bold design--was the celebrated, or
rather the notorious, Tom Paine, whose political writings Telford
had so much admired. The son of a decent Quaker of Thetford, who
trained him to his own trade of a staymaker, Paine seems early to
have contracted a dislike for the sect to which his father
belonged. Arrived at manhood, he gave up staymaking to embrace the
wild life of a privateersman, and served in two successive
adventures. Leaving the sea, he became an exciseman, but retained
his commission for only a year. Then he became an usher in a
school, during which he studied mechanics and mathematics. Again
appointed an exciseman, he was stationed at Lewes in Sussex, where
he wrote poetry and acquired some local celebrity as a writer.
He was accordingly selected by his brother excisemen to prepare their
petition to Government for an increase of pay, *[2] -- the document
which he drew up procuring him introductions to Goldsmith and
Franklin, and dismissal from his post. Franklin persuaded him to go
to America; and there the quondam staymaker, privateersman, usher,
poet, an a exciseman, took an active part in the revolutionary
discussions of the time, besides holding the important office of
Secretary to the Committee for Foreign Affairs. Paine afterwards
settled for a time at Philadelphia, where he occupied himself with
the study of mechanical philosophy, electricity, mineralogy, and
the use of iron in bridge-building. In 1787, when a bridge over
the Schnylkill was proposed, without any river piers, as the stream
was apt to be choked with ice in the spring freshets, Paine boldly
offered to build an iron bridge with a single arch of 400 feet
span. In the course of the same year, he submitted his design of
the proposed bridge to the Academy of Sciences at Paris; he also
sent a copy of his plan to Sir Joseph Banks for submission to the
Royal Society; and, encouraged by the favourable opinions of
scientific men, he proceeded to Rotherham, in Yorkshire, to have
his bridge cast.*[3] An American gentleman, named Whiteside, having
advanced money to Paine on security of his property in the States,
to enable the bridge to be completed, the castings were duly made,
and shipped off to London, where they were put together and
exhibited to the public on a bowling-green at Paddington.
The bridge was there visited by a large number of persons, and was
considered to be a highly creditable work. Suddenly Paine's attention
was withdrawn from its further prosecution by the publication of
Mr. Burke's celebrated 'Thoughts on the French Revolution,' which
he undertook to answer. Whiteside having in the meantime become
bankrupt, Paine was arrested by his assignees, but was liberated by
the assistance of two other Americans, who became bound for him.
Paine, however, was by this time carried away by the fervour of the
French Revolution, having become a member of the National
Convention, as representative for Calais. The "Friends of Man,"
whose cause he had espoused, treated him scurvily, imprisoning him
in the Luxembourg, where he lay for eleven months. Escaped to
America, we find him in 1803 presenting to the American Congress a
memoir on the construction of Iron Bridges, accompanied by several
models. It does not appear, however, that Paine ever succeeded in
erecting an iron bridge. He was a restless, speculative, unhappy
being; and it would have been well for his memory if, instead of
penning shallow infidelity, he had devoted himself to his original
idea of improving the communications of his adopted country.
In the meantime, however, the bridge exhibited at Paddington had
produced important results. The manufacturers agreed to take it
back as part of their debt, and the materials were afterwards used
in the construction of the noble bridge over the Wear at Sunderland,
which was erected in 1796.

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