Plan for Ehftittg a Bridge al Lonim, iS_tf i^^ 



ration of vitreous matter witii iron, as well as that which fliews that carbonic acid can produce 

 the fteel converfion, are new and important, cannot be qucftioned ; but whether the ufe of 

 carbonate of lime and clay, which is attended with fome lofs, may be preferable to vitreous flux 

 and coal, which afford fome fmall additional weight, is not yet, as it (hould appear, decided 

 by the adtual operations. 



SCIENTIFIC NEfFS. 

 Jcc Mints of Books, isfc. 



JLettcrs to a Merchant on the Improvement of the Port of London, demonftrating its Prac- 

 ticability without Wet Docks, or any additional Burdens being laid on Shipping, and at a 

 a lefs Expence of Time and Money than any other Plan propofed. By C. Dodd, 

 Engineer, 1799. 



THIS oftavo pamphlet, of nineteen pages, has been given away by the publiQier of the au- 

 thor's former Reports (Taylor in Holborn). The plan confifts in building a new bridge, ia- 

 ftead of, or upon, the prefent London-bridge, which fhall confift of one principal centre arch, 

 formed of iron, one hundred feet from low water to the crown of the arch, defcribing a fpan of 

 300 feet, with two large fliore arches of 80 feet fpan, as near to the butment on each fhore as 

 advifeable, for keeping deep water alongfide the prefent below -bridge quays. Among the ad* 

 vantages of the ftrufture, the principal is, that it will admit fliipping to pafs through, and ar- 

 rive at the fpace between London and Blackfriars-bridge, which, as the engineer obferves, 

 would contain above double the number of (hips propofed to be held in the new London docks, 

 which have been long in agitation ; at the fame time that it would be near the centre of 

 commerce, more than twice as cheap in time and money, and require no houfes to be pulled 

 down, nor eftabliflied courfe of induftry to be difturbed. 



The flope on each fide, which muft neceflarily be added to this ftrufture, is propofed to have 

 an inclination anfwering to three inches in the yard, and will then, as Mr. Dodd aflerts, ter- 

 minate, on the city fide, at Monument-yard, and on the Borough fide, near St. Thomas's 

 Hofpital. And this may be proportionally diminifhed, either in inclination, or in length, 

 by making the main arch, only 60 or 70 feet high, which, it is obferved, will afford the fame 

 advantages, provided the fliipping flrike their yards and topmafts. The evident advantages of 

 this plan are detailed at length, with confiderable animation, in thefe letters; in the fecond of 

 which, the fubjeft is confidered, as to, i. Pradlicability with regard to the eredlion. 2. Deep* 

 ening the river above-bridge. 3. The eredion of quays, wharfs, &c. 4. Facility of accommo- 

 dation to the commerce of the port of London. 5. Advantages of commercial tranfaftions 

 in rivers, beyond thofe in docks, and, in particular, of this plan, beyond the plan of the London 

 docks ; and, 6. The poflibility of completing this undertaking, without any expence being laid 

 upon the fliipping. 



In^confcquence of this difplay and elucidation of the fubjetS, a petition has lately been pre- 



fcnted 



