138 Progress in Science. [January, 



sidings at Paddington and Bristol, and the extension of the Llwynennion 

 branch. By another bill they propose to construct branches from the Cornwall 

 Railway to Devonport, and from the West Cornwall Railway to St. Ives. 

 The London and North Western Company are applying for powers to add 

 considerably to their system by the construction of lines in Middlesex, 

 Northampton, Rutland, Huntingdon, Stafford, Chester, York, Monmouth, 

 Carmarthen, Glamorgan, and Carnarvon, which are too numerous to mention 

 in detail. The South Western Railway propose a considerable extension of 

 their system by the construction of lines in Bucks, Surrey, Berks, and 

 Southampton. The Midland Railway propose several short branches at 

 Stockingford, Kingsbury, Ripley, Teversall, Duckmanton, Skegley, Bestwood- 

 Park, Holbeck, and one in connexion with the Metropolitan Railway at 

 Whitecross Street. The South Eastern Railway Company are applying for 

 powers to construct new lines at Rochester and Chatham, a junction line 

 between the South Eastern, New Tunbridge, and Paddock Wood and Maid- 

 stone lines. The proposed Staines and West Drayton Railway is a line 

 leaving the great Western line at Hillingdon, and terminating by a junction 

 with the Windsor branch of the South Western Railway at Staines. The 

 Swindon, Marlborough, and Andover Railway is a line from the Great 

 Western, at Swindon, to the London and South Western at Andover. 



Bridges. — An important engineering work is now under construction across 

 the Thames, at Chelsea, known as the Albert Bridge. The principle of its 

 construction is that known as Mr. Ordish's rigid suspension principle; this 

 system consists in suspending the main girders, which carry the roadway, by 

 straight inclined chains, which are maintained in their proper position by 

 being suspended by vertical rods, at intervals of 20 feet, from a steel wire 

 cable. The bridge, when completed, will have a total length of 710 feet, and 

 a width of 41 feet between the parapets. These will be formed of the main 

 girders, which are of wrought-iron, 8 feet deep and continuous, the upper 

 portions being ornamentally perforated in order to lighten and improve the 

 appearance of the structure. The main girders will be connected transversely 

 by cross girders placed 8 feet apart, and on these will be laid the planking for 

 the carriage roadway. There will be four towers carrying the main chains of 

 the bridge, and they will be placed in pairs, each pair being connected at a 

 height of 60 feet from the platform level by an ornamental iron arch. The 

 towers are of cast-iron, and consist each of an inner column 4 feet in external 

 diameter, surrounded by eight 12-inch octagonal columns placed 12 inches 

 from the central shaft, the whole group being connected together at intervals 

 by disc pieces or collars of cast-iron. The bridge is divided into a centre 

 and two side openings, the former a span of 400 feet, and the latter 155 feet 

 each. The foundations of the piers consist of cast-iron cylinders, the bottom 

 or cutting ring being 21 feet in diameter, and they are the largest cylindrical 

 castings ever made in one piece. From these the cylinders gradually taper 

 to 15 feet in diameter at the level at which the towers commence. The 

 cylinders are sunk down into the London clay, and then filled in with concrete. 



A paper has recently been read before the American Society of Civil 

 Engineers relative to the problem of how to sustain and maintain in position 

 the arch ribs of the Illinois and St. Louis bridge during the progress of its 

 construction. The most prominent novelty in the plan adopted consists in 

 the absence of all scaffolding or trestling standing in the river, excepting only 

 for a very short distance immediately adjoining the piers and abutments, sub- 

 stituting therefor a suspending system from above; also in using the inherent 

 stiffness of the arch ribs themselves as caulilevers, aided, if found necessary, 

 by temporary "-guys" from the piers and abutments, to support the derricks 

 and stages from which to project forward the successive sections of the ribs. 

 Space will not admit of our entering further upon this subject at present, but 

 we shall return to it again upon a future occasion, as it is one of extreme 

 novelty and well deserving of further notice. 



Channel Steamer. — Whilst the various schemes for rendering communication 

 between this country and the Continent are under consideration, — whether 



