New LONDON BRIDGE.—A cheesemonger, named Peter Jeffery, has, during nearly
the whole of the progress, and ever since the completion of the New London Bridge, amused and enlightened the small thinkers of the City with criticisms .on the structure of that work, and mr every thing connected with it. Mr. Jeffery is a man, to judge from his writ- ings—for he is a writer—possessed of all that frank assurance which is essential to prosperity in this bustling world, where, if a man do not elbow, he is almost certain to be elbowed; and as his knowledge and his modesty are neither so great as to stand in the other's way, so is his re- solution by no means of that puny character, that one, two, or twenty failures will suffice to break it down. Like the industrious insect, which still prosecutes, in its present humbled state, those labours for which it was once famous in a higher rank of being, when one web is swept away, Mr. Peter Jeffery can spin another, and another, and another ! Indeed, as in the case of the insect itself, there is for the most part but one way to get rid of the never-ending, still-beginning labours of such indefati- gable persons. While they live they must spin; and while they live they can never lack materials for spinning, inasmuch as they derive them entirely from themselves. Sometimes it will happen that their labours issue in good ; for there is nothing absolutely useless in the creation. He who gives the whole of his powers to one object, whatever be the amount of his powers, will now and then stumble on a fact which has escaped less minute observers. Arachne herself sees many little cracks and flaws in those nooks and corners to which she attaches her flimsy mansion, that were never dreamt of in the philosophy of the builder. So it has happened with Mr. Jeffery. He has gazed on the New Bridge with the sharpened eye of an amateur architect, until he has discovered that it has a very decided leaning towards the east,—whether out of a sneaking affection for its respected elder brother, or from a fellow-feeling with men of ordinary genius, who are generally observed to go with the stream, we do not pretend to determine. In either case, the New Bridge would have been obnoxious to Mr. Jeffery's censure, but especially in the latter ; it being a rule, with men of extraordinary genius like him, always to go against the stream. The discovery of the leaning of the Bridge, arising from what cause it may, Mr. Jeffery immediately pub- lished; and in order that it might be as widely known as possible, he sent an account of it to the House of Commons, in the shape of a peti- tion. This was a bold step, but what will not mortal hearts dare ? The House of Commons received the petition; and, as the permanency and stability of a new structure very naturally associated itself with the Bill, they immediately communicated the intelligence it contained to the Bridge Committee ; and the Bridge Committee, as in duty lound, have set on foot an examination into the alleged evil inclination of the Bridge. The result has been a long and curious report from Messrs. Telford and Walker, from which we shall quote a few passages.
Of the general appearance of the work they speak in terms of the highest praise.
" Before proceeding to any detail, it may be proper to observe, generally, that although there is an irregularity in the levels, and in the face of the work, which we shall afterwards have to describe, the only pier in which we could discover the smallest appearance of fracture, was in a few stones of the third pier ; and even that has no appearance of being recent, and is so small that we were doubtful if it did not arise from natural defects, or joints in the stones themselves. So far as we can discover, no pains have been spared in regard to the materials end workman- Ship. We observed only a few cracked arch-stones in the whole bridge ; and even the may.have been caused by imperfections in the particular stones, which are sometimes not discoverable until a pressure comes upon them. The parapet of the bridge is as perfect a specimen of granite work as any we have ever seen." Into the listory of the tedinical means employed for ascertaining the deviation from the perpendicular, of which Mr. Jeffery had ntride so alarming a report to the House of Commons, we need not enter. The deviation ascertained, the architects set about endeavouring to ascertain its cause. There are two theories afloat,—the workmen attribute the leaning to a slight inaccuracy of level in the platforms on which the foundations of the piers rest ; the second theory attributes it to an irregu. . larity in the settling of the foundation. Messrs. Telfoed and Walker observe- . If we had the surrey and our own obserw,!if. !.. • slic old have
concluded that nearly all the irregularities had • • ' .•■ -:ents, which would account for the effects we have (lest, • '. •.., . e no douht that the forming an uniformly good foundation te • - . ,e, i. t .e great depth and other causes, must have been a work of much • ; WaS increased by the piling being driven into clay that was stated ta be seyerti feet higher at the west than at the east end, and which the driving of the piles unavoidably tended to disturb and loosen. Under such circumstances, althonelt any settlement in such a work would be to be lamented, there would have been malting difficult to account for.
"The other position—viz. that the first platform was had on a slope, and that all the others, and all the work above in all the piers, and up to the completion of the bridge, should have been made to correspond with the first error—would Imply a difficulty of execution, to say the least, which is net easy to account for. Thepoints of the piers, the faces of the walls, and the courses of stone-work through the piers, are, with little exception, in straight lines, battering or overhanging, or sloping at the places where the irregularities are, but all nearly corresponding ; that is, if the courses of stone In the piers are out of level, the ends of the piers and spandril walls to the top of the arch, are nearly proportionally out of perpendicular, but still suffi- ciently straight, and it Is not easy to suppose them to have been built so. We do not think the statement of the stones being so square, as that the work, when Once begun on an Inclination, naturally continued to slope sad batter to the end, without the superintendents or workmen being aware of it, sufficient to account for the irre- gularities to the present extent. If we are correct in our opinion, there being a set- tlement in the foundation without any fracture in the work, can only be accounted for by the excellence of the masonry; the work being so bonded and cemented to- gether as to form one mass. and the strength of the stonework of the piers, to resist a fracture in the vertical direction, being greater than the resistance of the founda- tion to yield under a pressure. It is to be rernarked also, that the parapet was set after the centres were struck, and perhaps after any settlement had taken place. Still it is difficult, even with the above considerations, to suppose the irregularities to the extent we have described to have taken place from settlements, and yet that scarcely any crack or fracture shoold be visible; and we cannot, after the evidence we have received, conclude that the foundations were laid quite level. That the pre- sent state of taings has arisen in some degree from the foundations not haying been laid quite level, but principally from a settlement afterwards, has, therefore, upon the whole, the greatest appearance of probability." Of the nature of the foundation, the report speaks in the following terms.
"The evidence that has been glven by the engineers, contractors, and every wit- ness we have examined, states not only that every pier and every part of each pier was founded upon very hard solid clay. but that it cenisiderable thickness of it was removed to get to the depth at which the foundations are laid. This fact they de- scribed as having been quite notorious; and we beve mentioned that two rows of the dam-piling were left in front of and round the east ends of the piers far protecting the foundations. We must, however, state, that from our seundings in the middle of the centre arch, the bed of the river at that place is ziaw about two feet six inches under the level of the top of the platforms ; anti also, that the evidence above stated as to the level of the clay, does not agree with the borings taken under Mr. Telford's directions by order of the Britigehouse Committee in "'These describe the rubbish and loose soil near the east end of the second pier from the Sorry side, and the fourth or Middlesex pler,to be considerably below the level to which the tops of the bearing-piles have been driven.. If this were to be taken as correct, it would affect the question as to the stability of the piers ; but excavations made within cofferdams are more certain than timings in a riser; and the evidence to which trehave referred has been so decided, and from so many wit- nesses, that we are bound to admit its correctness." The injurious effects of the settlement or irregularity, will depend, of course, mainly on the fact of its being recent or old. " If the foundations," continues the report, "were laid, and the bridge built, with the present irregularities, as the evidence of most of the witnesses would lead US LO beliese—and if there has been no movement in the foundation at all,—then there is no reason for apprehending danger now; and although the present imper- fections would still be to be regretted, they would not affect the stability of the structure.
"Again, supposing a partial settlement to have taken place during the progress of the work, if there has been no movement within the last two years (and the evidence of the resident engineer on this point is strengthened by the appearance of the work generally, and particularly of the parlpet, which we tinderstand eras nearly all set before Christmas last), then it is reasonable to conclude that the whole has come to its proper bearing." This question Messrs. Telford and Walker can for the present only determine by testimony, all of which concurs in stating that no altera- tion has been observed in the Bridge for two years past; kit they have adopted measures for subjecting it to the test of future observation, which is less liable to deceive. They speak of the bed of the river as being at present below the level of the platforms; but this seems very doubtful, and Sir John Rennie expressly contradicts the statement. In the mean time, they advise the cautious removal of the Old Bridge, and the placing of a quantity of the stones taken from it rotund the piers of the New, with a view to defend them from the effect of those eddies under which the bed of the river is supposed alreedy to have greatly suffered. The whole investigation is interesting. If the New Bridge were te fall, great indeed would be the fall thereof. It is unnecessary to say, that Sir John Rennie and Sir Edward Baukes laugh the notion to scorn: What will Mr. Jeffery do next I
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