1839.] 



THE CIVIL ENGINEER AND ARCHITECTVS JOURNAL. 



393 



fisb were killed by the first explosion, but none Ijv those which fol- 

 lowed, and it is natural to suppose that the noise and shock would 

 drive those fish to a distance which it did not kill outright. 



On the 22nd ult. Colonel Pasley veneweil his operations, and with 

 the usual success which attends well-directed perseverance, at length 

 succeeded in tiring off one of the enormous sub-marine mines of gun- 

 powder against the wreck. A cylinder, containing 2,32iilb. of powder, 

 was carefully lowered to the bottom, where it was placed alongside 

 the most compact portion of the wreck which has yet been disco- 

 vered by the divers. This operation was eHijcted by means of haul- 

 ing lines rove through blocks attached to the bottom of the ship In' 

 the divers. Wlien everything was ready, the vessel in which the 

 voltaic battery was placed was drawn uli' the distance of 5W) feet, 

 which i.s the length of the connecting wires, and instantaneously on 

 the circuit being couii)leted the explosion took place, and the elfects 

 were very remarkable. At first the surface of the sea, which had 

 before been perfectly smooth and cahn, was violently agitated by a 

 sort of tremulous motion, which threw it into small irregular waves, 

 a few inches only in height. Tliis lasted for three or four seconds, 

 when a huge dome of water made its appearance, of a conical or 

 rather beehive shape. At first it appeared to rise slowly, but rapidly 

 increased in height and size till it reached the altitude of 28 or aU 

 feel, in a tolerably compact mass. It then fell down and produced 

 a series of rings, which spread in all directions. The first, or outer 

 one of these, having the aspect of a w'ave several feet in heiglit, 

 curled and broke, as if it had been driven towards the shore. Neither 

 the shock nor the sound was so great as had been expected by those 

 who had witnessed the former explosions by Colonel Pasley, where 

 the quantity of powder was only 451b. ; but the effect produced on 

 the water at the surface, considering tliat the depth was 90 feet, was 

 truly astonishing. What the eli'ect has been upon the wreck will not 

 be fully ascertained by the divers till the present spring tides are 

 over, and the long periods of slack water at the neaps enable the 

 divers to remain for upwards of half an hour under water. In the 

 mean time, it is highly satisfactory to know that Colone\ Pasley has 

 completely established his command over the application of the 

 voltaic batteiy to siib-marine purposes, and that he can now with 

 certainty explode his charges at any depth of water. This w ill give 

 him the power of placing his cylimlers against the most refractory 

 parts of the wreck, and by blowing these to pieces, and dislocating 

 the knees, timbers, and beams, enable him to draw the wdiole u[>, bit 

 by bit, to the surface. Any person who has seen the operation of 

 breaking up a ship on land, knows that this is the only way <jf going 

 to work with a mass so firmly bound together as a line-of-battle ship, 

 that even the action of 57 years of decay under water goes but a 

 small way to disintegrate the parts. The manly perseverance of 

 Colonel Pasley, therefore, we are well convinced, will, in the end, 

 effectually clear the noble ancliorage of Spithead of tills extremely 

 troublesome obstruction. — Times. 



LOCOMOTIVE POWER APPLIED TO CANAL TRANSIT. 



On the 21st and 22nd of August an experiment was conducted on 

 the Forth and Clyde Canal, of a novel and highly interesting nature, 

 by John Macueil, C.E., and consulting engineer to the Canal Com- 

 pany. It is well known that the haulage of boats on this canal has 

 hitherto been performed by horses, the rates of speed being for the 

 heavy sloops, brigs, ice, in the London, Dundee, and other trades, 

 about li to 2 miles per hour, when drawn by two or five horses, ac- 

 cording to the state of the weather, and for the swift or passenger 

 boats between S and 9 miles per hour, on an average, when drawn by 

 two horses. The object of the experiment was to ascertain the pos- 

 sibility of using locomotive steam power to draw the boats instead of 

 horses : accordingly, a single line of rails, upon blocks, like an or- 

 dinary railway, was laid down for a considerable space along the canal 

 banks, near lock IG ; and a locomotive engine and tender, built by Mr. 

 William Dodds, having been brought down the canal and set on the 

 rails, on the morning of the 2 1st, Mr. Macneil, Mr. Johnston, the 

 canal director, and several engineers anjl gentlemen, being present, 

 the experiment commenced by attaching to the engine the towing- 

 line of the first passenger boat that made its appearance, and which 

 contained upwards of 90 passengers, with their luggage. There w as 

 a trifling delay in disengaging the horses and tying the line to the 

 engine, but this was amply compensated when the "Victoria" briskly 

 set otf, and almost immediately gained a speed of i7i miles per hour, 

 which she kept up round two curves, and until the termination of the 

 rails made it necessary to stop, amid the cheers of the delighted pas- 

 sengers. This experiment was repeated, during the course of the 

 day, with each passenger bout as it came tQ the railed space, and 



with equal success each time. On one occasion a towing-rope, which 

 was nuicli decayed, got foul with a curb-stone and broke, but without 

 causing the slightest inconvenience, except about one minute's delay. 

 Tl'.e engine employed being intended only for a slow trade, was not 

 calculated to go at a greater speed than eighteen miles per hour; but 

 it was the opinion of all present, that with proper p;issengcr locomo- 

 tives, a speed might be obtained equal to that upon the best railways, 

 few of the latter possessing the advantage secured by the canal bank 

 of a pei/L d level throughout. 



The nature of the motion was liighly gratifying to all tlie [lassen- 

 gers, being more uniform, steady, and smooth than when the boats 

 were d.awn by horses. 



.Several of the heavy (masted) vessels were also taken in two 

 during the two days of trial, at the rates of 3, 3i, 4, ;uid 5 miles per 

 lionr ; and, on one occasion, two loaded sloops, and a large waggon 

 boat, were together attached to the engine, and hauled with ease at 

 the rate of 2i miles per hour, wdiilst only one-fourth of the steam was 

 allowed to pass the throttle -valve. 



The foregoing statements render palpably apparent the immense 

 advant.iges which might be gained by this new adaptation of steam 

 power — a great economy in haulage expenses, as one engine might 

 draw at least (i sloops, which now would require from eighteen to 

 twenty-four horses, and, if necessary, at double the present speed ; 

 and a proportional increase of the important traffic on the canal, 

 which might be reasonably expected. 



Passengers would increase in a great proportion, when attracted by 

 economy and speed of trans[iort. The Union Canal might be tra- 

 versed in two hours, and the Forth and Clyde Canal in one and a 

 half, instead of fovir hours and three and a half, as at present, and 

 this by only assuming IG miles per hour, though more niiglit easily 

 be performed, as the experiments have shown. — Glagojo Coiirtir. 



THE EXPERIMENTAL PAVING OF OXFORD STREET. 



The extended time allowed by the Marylebone vestry for testing 

 the durability of the various specimens of experimental paving laid 

 down in Oxford-street having expired on the the 3rd ult. a large body 

 of the members of the Experimental Paving Committee proceeded 

 to Oxford-street, for the purpose of entering into a minute examina- 

 tion of the specimens, prior to completing their final report and re- 

 commendation to the vestry as to the plan which it would be most 

 advisable to adopt. The blocks of granite laid down, and the inter- 

 stices of which are tilled up with Claridge's Asphalte, was found to 

 be in excellent condition, as was also the granite laid down by the 

 parish and grouted together. The Bastemie Gaujac bitumen had 

 stood the test of the wear occasioned by the number of vehicles 

 passing through this extensive thoroughfare in a surprising manner, 

 but at parts where the trattic is most severe here and tliere, slight 

 ruts are perceptible. On arriving at the wooden blocks, the surface 

 was found to be as smooth and even as when first laid down. Five of 

 the blocks were taken up and minutely examined by the committee, 

 and one of them split into pieces for the purpose of discovering if 

 any symptoms of decay liad made its appearance, but the wood was 

 found to be perfectly sound, and the diminution of the length of the 

 blocks (12 inches), notwithstanding the immense weight of the ve- 

 hicles continually passing over them, was scarcely perceptible. Having 

 completed their survey of the road, the conunittee adjourned to the 

 Court-house for the purpose of deliberating as to the best mode to 

 be adopted, when a long discvission ensued upon the subject. Mr. 

 Kensett supported the adoption of the wood, and Jlr. Harbutt and 

 several others opposed it upon the gromid that the material was of 

 too slippery a nature for horses. After a variety of arguments, in 

 the course of which three or four amendments were put and nega- 

 tived, the following resolution was put and carried — viz. "That it 

 appears to the conunittee that the wooden block paving has proved 

 itself equal to the traffic and paving of the whole of Oxford-street, 

 and it is, therefore, resolved to recommend to the vestry to adopt the 

 wooden block paving for that thoroughfare, subject to certain condi- 

 tions and regulations." The greatest interest is manifest on this sub- 

 ject in Marylebone. 



Engraving on M arbi.k. — A discovery of some importance to the statiiai y 

 lias receutly been made by Mr. C. Page, of Pimlieo, Ijy means of vvliich en- 

 graving ou marble is greatly iiiiprovert. lu cutting letters in niari)le in the 

 or(Uiiary method, the edges chip otl', and tlie defects are covered by paiuting 

 them over ; but Mr. Page obviates this difficulty by covering the surface of 

 the polished marble with a coat of cement lieforc the chisel is used. The 

 cement effectually prevents the marble from chipping ; and when the cuatijii; 

 is removed, the letters remain as iierfcct as if cut in copi'sr. 



2 K 2 



