Chap. VIII.
BRITAIN.
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the architect, he will be superseded by the engineer; there is no reason why the labour ofnecessity or usefulness should not be embellished by taste, and a great nation has a right toexpect the union of science and art, based on the severest integrity, in those to whom millionsare entrusted for her improvement.
It is not possible to form an estimate of the sums expended by individuals and companiesduring the last century on roads, bridges, canals, harbours, docks, and mining operations,where the services of the engineer were demanded; that the amount exceeds that of thenational debt there can be no doubt, and a thousand million sterling would not be overratingthe total outlay. Many of the bridges have cost upwards of a million, and the railwayscompleted considerably more than a hundred million ; how much of this vast sum has beenimprovidently expended cannot now be estimated, but probably more than half. We mayconsider that to the middle of the last century, the drainage of the land, the embankment ofrivers, and the extracting of ores, was performed by individuals who had no claims to thetitle of civil engineers ; it was his knowledge in mechanics that induced a member of theIloyal Society to select Smeaton as the builder for Eddystone Lighthouse . In the middleages towns and cities were walled in, and castles and cathedrals built, by the enterprisingconfraternities of Masons, who travelled from place to place under the direction of agoverning body : to them were confided constructions of every kind, and the intelligent headof the Lodge acted as architect and engineer; old London Bridge , and the walls whichsurrounded Dover, Hartlepool , and other harbours, evince their skill in such constructions.The same causes which led to their dissolution buried for a time the knowledge which hadrendered such important service to the country ; but when internal tranquillity was restored,the whole extent of our coast, and the navigable rivers which discharge themselves intothe ocean, received improvement, though this was often effected by men who had obtaineda reputation abroad ; vast tracts of land were redeemed from a state of marsh by engineersfrom Holland: all these important undertakings were conducted in a rude and imperfectmanner; the philosopher had not directed his studies to what was useful, and mathematicalknowledge was slighted by the unlearned practitioner.
The Ports and Harbours of Britain first claim our attention, and although it is notpossible to do more than briefly describe them, we may, where information is afforded, givean account of some of the improvements they have undergone ; it must, however, be admittedthat much remains to be performed, before they will answer the growing wants of ourgreat commercial intercourse.
' The Thames , that gentle, deep, majestic king of floods, seems to have been the resort ofcommerce at a very early period, ’and on its banks, where the capital is now situated,formerly stood Llyn-Din, or the town on the lake. This river, which is of such im-portance to British commerce, passes through a rich and fertile district; the basin of theThames , or the land it drains, has been computed as equal to an eleventh part of Englandand Scotland , and as containing nearly a fifth of the entire population. It rises on theCotesw'old hills, and receives its supplies at first from the Lech, the Colne, the Churne, andthe Isis; the latter flows by Cricklade, and is rendered navigable for small craft atLechdale, on the confines of Gloucestershire and Berkshire. The Windrush and Evanloderun into it a little below', and at a short distance further the Thame enters it near Dor-chester; the whole is then called Thame Isis. After passing Reading, it receives theKennet, and below Staines the Wey ; when flowing through the metropolis, it has othertributaries in the Lea, the Ravensbourne, the Darent, and the Medway.
From Lechdale to London Bridge , the distance by the river is 146J miles, with atotal rise from low water mark, at the bridge, of 248 feet; the tide flow's up 18*j miles, toTeddington, w’here is the first lock to aid the navigation. The low' water surface of theriver falls about 16 feet 9 inches from Teddington lock to London Bridge , or 10} incitesper mile on an average. The high water mark at Teddington is 18 inches above the highwater mark at London Bridge , and the time of high water is later by about two hours.The fall of the bed of the river in this distance is about 12 inches in a mile.
The Thames flows with a regular and steady current, and is of a considerable depth aboveGreenwich ; at ebb tide it is generally from 12 to 13 feet; the tides at London Bridge riseordinarily about 17 feet, and at extreme springs as much as 22 feet. Ships of almost anytonnage can get up to Deptford ; those of 1400 or 1500 tons to Blackwall, whilst St.Katherine’s Docks will not receive vessels of above 800 tons.
The whole course of this noble river measures upwards of 200 miles, and it drains asurface of country equal to about 5000 square miles ; its meandering is considerable, as astraight line drawn from its two extremities is not much more than half the before-men-tioned distance. Its velocity varies from ^ mile to 2| mile9 per hour, and the mean hasbeen computed at about 2 miles per hour.
On the southern banks, below London Bridge , are many docks, and the governmentestablishments of Deptford , Greenwich , and Woolwdch, and on the Medway, Chatham andSheerness . On the northern banks are several docks, belonging to the St. Katherine,
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