1850.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



271 



and be slightly rounded on the inner face to allow the rail to 

 adjust itself to the joints, which are first keyed and spiked firm. 



Fig. 2 shows a section of thu common switch, which possesses 

 the advantage of a straight face and continuous bearing surface; 

 but in consequence of it consisting of two parts, is mucli less 

 durable at the point than the improved switch. 



Fig. 3 is a section of the patent switch. 



Fig. 4 is a section sliowing the cant of the rail in the chair. 



Fig. 5 is a section of a check rail chair. 



Fig. 6 is a plan of a crossing point. 



FLOATING OF THE FOURTH AND LAST TUBE OF 

 THE BRITANNIA BRIDGE. 



The floating of the fourth and last tube, which may be said to complete 

 this mazniticent structure, came otf oi\ Thursday morning, tbe 2otli ult., at 

 9 o*clock, with success. 



The interest that has throughout been associated with these great engineer- 

 ing performances was probably heiglitened on the present occasion from the 

 fact of its being the last great launching operation of the kind likely to occur 

 iu this country, and accordingly, the concourse of people present frimi all 

 parts was estimated to be not far short of the thousands who thronged the 

 Straits on the occasion of floating the first tube. 



At the above hour Mr. Stephenson, M.P., Captain Claxton, Mr. Edwin 

 Clarke, Mr. Bidder, Mr. C. H. Wild, Mr. Ilicardo, M.P , Mr. Lee, C.E., Mr. 

 Borthwick, C.E, and others, took their stations on the top of the tube, which, 

 araid the cheers of the multitude, gradually, as the tide came up, rose upon 

 its cradle of pontoons. The men at the mooring-chains and capstans then, 

 in obedience to the various signalings and coloured flags, plied away at their 

 posts, until at three minutes past 9, the huge mass, when released from its 

 moorings, moved out into midstream, where under the control of the vast and 

 intricate tackle, it made its way for full 40 minutes, until in the space of 

 another ten, and after various nice evolutions, it came home and was safely 

 deposited, amid artillery and cheers, on the projecting plinths of the towers. 

 The tide taken at starting was 12 ft. 8 in., and it gradually rose until it reached 

 a maximum of 17ft. The total distance travelled over from the starting point 

 on the Carnarvonshire coast to the base of the towers was upwards of 300 

 yards. At about four minutes past 10, just as the operation was completed, 

 the tide turned and it was high water at 32 m. past 10. The length of the 

 tube floated was 470 feet; its weight, 1690 tons; the number of pontoons, 8; 

 their aggregate burden, 2750 tons; the number of men engaged in the floating, 

 68j. During the operation, the spectators were permitted to stand upon the 

 tOji of the tube already iu use, and which was covered with them from one 

 end to the other. The completion of the bridge will cause the Chester and 

 Holyhead Company to dispense with nearly 1000 workmen, who since 

 the commencement of the works, with their wives and lamilies, have been 

 in constant occupation. The hydraulic presses are on the towers and will 

 commence lifting almost immediately. The tube that has been in daily use 

 since the 18th of March last, has presented to the most careful observation 

 no change or alteration up to this time. The deflection found to be caused by 

 the passage of ordinary trains daily is two-tenths of an inch, and some 

 extreme heavy coal trains have deflected it as much as half-an-inch. The 

 effect of joining the several tubes together, and lowering the opposite end, 

 has been to raise them four inches, so that the most heavy trains do not 

 counteract more than oue-eightb of the advantage that was gained by this 

 process. 



An early day in November next is ofEcially announced by the engineers 

 as the period for the consolidation and complete public opening of the bridge. 



MOTES OF THE SIOHTH. 



Exhibition Buii-ding. — Another estimate has been sent, by another 

 party, to the Royal Commission for the Exhibition of 1851, oflfering to con- 

 struct a building similar in dimensions to that of Mr. Paxton, but in iron, in 

 place of glass, for the sum of 40,000/., the material to be returned to the 

 contractor. If this offer be accepted, there will remain out of the 04,000/. 

 subscribed a balance in hand of 24,000/. for other expenses of the Exhibi- 

 tion. Whereas, the estimate of the glass building being 85,000/., will leave 

 a deficiency of 21,000/.; and if to that sum we add 24.000/. for other ex- 

 penses, it will make in all a deficiency of 45,000/. Moi cover, the risk will 

 be avoided of the calico, intended to cover the glass building, being fired 

 with squibs or crackers, or Ijy some accidental sparks from the neighbouring I 

 chimneys, which, in all probability, would soon break the glass acid fire the 

 goods within, — and thus terminate the Exhibition with as much confusion as 

 it has begun. 



A model of London has been made for the Exhibition of 1851, on a 

 scale of eight inches to the mile, and containing in alt ninety-six square 

 feet. We understand that it exhibits the exact situatiou of all the public 

 builJinga, churches, bridges, railways, itr., with ihe Thames from Batter- 

 sea to Kotherhithe, and shows the dillrreut clevalious of the streets. 



Death of Robert Stevenson, Esa., C.E. — It is with extreme regret we 

 have to announce the death of Mr. Stevenson, the civil engineer, an event 

 which took place on Friday, the I3th inst. Mr Robert Stevenson, had reached 

 the advanced age of 78. The contemporary of Telford, Rennie and Stephen- 

 son (of England), needs no biography beyond an enumeration of his works. 

 Mr Stevenson, it will be remembered, was the sole designer and executor of 

 the celebrated Bell Rock Lighthouse, which is in itself a monument of inge- 

 nuity and industry. Sir Walter Scott, in his diary, mentions Mr. Stevenson 

 in terms of admiration, and bis impromptu in the album of the Bell Rock 

 Lighthouse is well known. Mr. Stevenson first brought into notice the 

 superiorityof mallcableiron rails forrailways over tbeold cast-iron, afact which 

 has been fullyacknowledged. lie also surveyed the line between Edinburgh and 

 Glasgow, and though his plan was not adopted, it was much admired. The 

 coast of Scotland, however, is ihe place where the labours of Mr. Stevenson 

 are principally to be seen. Not a harbour, rock, nor island, but bears evi- 

 dence of his indefatigable industry, and it is incalculable to think of the amount 

 of life and property which by his exertions, have been saved. In matters re- 

 lating to the construction of harbours, docks, or breakwater, he was generally 

 consulted as an authority; and received, as a mark of respect and admiration, 

 a gold medal from the late King of the Netherlands. We may mention 

 that in private life nothing could excel the amiability and good heartedness 

 of Mr. Stevenson. His courtesy on all occasions was such as to render him 

 popular with all who desired access to bis presence. — Scoltish Railway 

 Gazette. 



The Great Bull from Nineveh. — The lovers of art will be pleased to 

 hear that the Great Bull and upwards of 100 tons of sculpture, excavated by 

 our enterprising countryman, Ur. Layard, are now on their way to England, 

 and may be expected in the course of September. In addition to the Elgin, 

 Piiigalian, Lycian, and Boodroom marbles, our museum will soon be enricheit 

 with a magnificent series of .-Assyrian sculptures. It is said at Nineveh that 

 the French Government are determined to excel us in the exhibition of Assyrian 

 works of art in order to compensate the comparative deficiency which the 

 Louvre is obliged to acknowledge as to the treasures it possesses in the other 

 great catalogues, and that large sums have been accordingly voted for the 

 expenses of excavation. A drawing which represents the shipping of the 

 sculpture has been just brought over by one of the .Messrs. Lynch, of Bagdad, 

 who has been with Dr. Layard exploring the remains of Nineveh. It repre- 

 sents the actionof placing the great Bull on hoard the Apprentice, at Morghill, 

 on the right bank of the Euphrates, about three miles above the old city of 

 Bussorah. This place long formed the country residence of Colonel Taylor, 

 lately the political agent of this country at Bagdad and Bussorah, and is now 

 rented by Messrs. Stephen Lynch and Co., to the Hon. East India Company, 

 as a depot for their vessels on the Euphrates. Alongside the Apprentice is the 

 Nicotris steamer, under the command of Captain Jones, I.N., whose influence 

 with the natives is most powerful, and to whose assistance the success in 

 effecting the difficult operation on the muddy and deserted banks of the 

 Euphrates is in a great measure attributable. The Apprentice was sent out 

 from this country by Mr. Alderman Finnis, at the instance of the trustees 

 of the British Museum, and to that gentleman and his nephews, Messrs. 

 Ljncb, the public are indebted for a periodical communication between the 

 Thames and the Euphrates. Another vessel belonging to the alderman is, 

 we understand, about leaving London, and it is hoped that she may in like 

 manner return home laden with the monuments and trophiesof what we had 

 been too apt to regard as the semi-fabulous metropolis of the ancient 

 world. 



Isthmus of Panama. — The news from the Isthmus is unfavourable to 

 the early construction of the railroad between Chagres and Panama. Im- 

 pediments had occurred which were never contemplated, and, if the work 

 is not entirely abandoned — as it is supposed it must be — it will at all events 

 be many years before it can be completed, at a cost, too, compared with 

 which, the original estimates are trifling. Such is the publicly avow-ed 

 opinion of those who are best informed on the subject. Important modifi. 

 cations of the contract had been obtained from the Congress of New 

 Grenada, among which is the conclusive privilege of constructing a plank or 

 wagon road for temporary purposes. The immediate opening, however, of 

 the less fatiguing, less distant, and perfectly salubrious route throug Nicara- 

 gua by the Atlantic and Pacific Ship Canal Company, will undoubtedly do 

 away with the necessity even of this substitue for a radroad, by monopolis- 

 ing, as it must do, tue whole traflic of the Isthmus. 



Gas. — There are now in England and Wales 560 proprietary gas-works, 

 and in Ireland and Scotland 170. Besides these there are thirty-three 

 which belong to private individuals, and twelve the property of municipal 

 bodies or parish officers: in all, 775 distinct establishments for the manu- 

 facture and sale of gas. In these works a capital of 10,500,000 is said to be 

 invested. The quantity of gas annually produced is about 9000,000,000 

 cubic feet, and thecoal consumed in making it weighs 1,125,000 tons. The 

 number of persons employed in its production is about 20,000; and pro- 

 bably an equal number finds employment in the preparatory work in the 

 mines, ironworks and other processes connected with it. After allowing for 

 waste and leakage, the quantity of gas actually sold to the public, in the 

 year, is about 7200,000,000 feet, producing a light equal to vvhat would be 

 given out by 32,133,640 gallons of sperm oil; which at eight shillings a 

 gallon would cost the consumers 13,253,456/. The gas itself is charged by 

 the Cijmpanies about 1,620,000/. 



