230 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[July, 



resolved to fire the red-hot shot 32-pounders, at a range of 800 yards. Tlie 

 first of these entered at the bottom of the coal-box, nearly in the same line 

 with the bull's eye, and set fire to the wood work, which continued to burn 

 slowly along with the ignited coals. The second red-hot shot entered about 

 three icet from the bull's eye, and so lodged amongst the coals that it was 

 full a quarter of an hour before the smoke of the ignited coals could make 

 its way through the hole where the shot entered, and at the top of the box, 

 I)ut it afterwards rapidly gained an ascendancy, and would have consumed 

 the whole had not the fire been put out by a party of men with the fire 

 engine. The experiments were concluded by firing an 8-inch shell from a 

 battery, at a distance of 950 yards, and it struck in a horizontal line with the 

 bull's eye, tearing the eastern side of the coal-box, and exploding when it 

 reached the back part of the box, scattering the coals, fragments of shell, 

 and wood to a considerable ilistance. 



It is probable the result of these experiments, which have been so far satis- 

 factory, will give rise to others of a similar nature, as they appear to be of 

 great importance. Were the coal boxes maile of iron half an inch thick, 

 instead of a quarter of an inch.as theone experimented with, itwould afford, 

 especially at the back, a more secure hold to the rivets of the joinings, the 

 only parts which may be considered as having given way during the severe 

 tests. The action of the loose coals appears to have a great effect in pre- 

 venting balls passing through them when about six or seven feet in thickness, 

 and placed in an iron box, and the discovery may prove of great importance 

 in future fortifications, and in the defence of important stations. 



IMMENSE BL0C:K OF STONE, SHIPPED FOR THE NELSON 



MEMORIAL. 



On Thursday, 9th June, we had the pleasure of witnessing the arduous 

 undertaking of putting on ship-board this huge block of stone, weighing 

 30 tons, intended to form the lower part of tlie figure of Nelson. This 

 beautiful piece of liver rock, when first detached from its original site in 

 Granton quarry, was 45 tons, its under bed resting 16 ft. 3 in. below the 

 datum line of low water at Granton Pier. It had, therefore, to be raised a 

 perpendicular height of 40 ft. over the inclined plane of the railway leading 

 cut of the quarry to the summit level. 



It was first conveyed over the floor of the quarry nearly on the level 73 ft., 

 then up an incline ^6 ft. long, having a rise of II ft. 9 in., a second incline 

 430 ft. long, having a rise of 26 ft., a third incline 112 ft. long, having a rise 

 of 2 ft. 3 in. 



This was accomphshed in three days by means of logs of limber laid 

 down, covered with a strong flat iron bar, and malleable iron rollers 34 in. in 

 diameter, and hauled by strong purchase crabs ; nearly another day was 

 occupied in placing it on a wagon built for the purpose, and conveying it 

 along the railway to the place of shipping, opposite the old castle of Granton, 

 where a dock was excavated to admit the vessel coming alongside the rock, 

 ivhere the shears and other powerful apparatus were fixed. 



Mr. Cole, wlio was entrusted with the management of shipping this gigantic 

 block, and the Government stores for the purpose, has been eminently success- 

 ful in his hazardous task. It appears, that to test the apparatus and ascertain 

 if every part was properly proportioned and efficient, on Wednesday one of 

 the tliree blocks required to complete the figure, weighing 13 tons, was 

 shipped, Bnd every part of the beaiing acting perfectly satisfactorily, it was 

 determined to ship the large one on the follo»ing day, should the tide flow 

 sufficiently high. At half-past one o'clock we were on the spot, when the 

 stone had been already hoisted, and in suspension between the ponderous 

 shears, all hands anxiously waiting for the vessel. The Albion of Goole, 

 Captain Wright, was placed alongside, there being then scarcely sufficient 

 •water. Precisely at two o'clock the vessel being hauled into her berth, the 

 process of lowering the shears to the required angle being accomplished with 

 great accuracy, the purchase tackles began to move, and so gradually and 

 steadily was all this managed, that not the least creak or surge was percep- 

 tible in any part. 



In 20 minutes from the commencement of lowering away, the vessel having 

 received the block, which put her down exactly a foot, was hauled into deep 

 water.'] iAlthough a great number of people were congregated, not the 

 slightest noise or confusion occurred : every one seemed highly gratifled, 

 from their giving three hearty cheers, on the vessel being hauled out. 



His Grace the Duke of Buccleuch has made a present of these fine blocks 

 to the committee of management for the memorial, and we feel happy in 

 announcing their being safely shipped without the slightest accident. 



We were happy to bear Mr. Cole express his sense of the kind attention 

 and assistance received from Mr. Hawkins, resident engineer, and Messrs. 

 Orrell and Wighlman, contractors, Granton Vkr.— Edinburgh Evening Post. 



MR. VIGNOLES' LECTURES ON CIVIL ENGINEERING, AT THE 

 LONDON UNIVERSITY COLLEGE. 



SECOXD COrRSE. — L'ECTURE VI. ON THE GAUGE OF RAILW.VVS. 



After some preliminary observations, illustrating parts of the last lecture, 

 and particularly in reference to w'hat was stated respecting the Brighton 

 railway, Mr. Vignoles proceeded to enter on the subject of the breadth or 

 gauge of railway, which he explained to denote the distance between the 

 iron bars which form the track or way. The definition of the gauge of the 

 old tramways, introduced the observation that, from their form being as it 

 were an artificial rut, they were styled by the French ornigres, of which the 

 literal translation was " wheel-rut." The present ordinary railway gauge 

 was 4 ft. 8J in., and some speculations were made as to the choice of such a 

 particular breadth ; and quotations were made from Mr. Wood's Treatise on 

 Raihmys to show that it had been owing tn an accidental circumstance — viz. 

 that the first conclusive experiments on the principle of the present loco- 

 motive engines had been made on the Killingworth Colliery railway, which 

 was laid to that gauge. In some of the first of the Acts of Parliament for 

 modern railways, it had been made imperative by a special clause to adopt 

 this particular gauge, and many companies submitted quietly to the enact- 

 ment, thereby preventing all chance of improvement in what was assumed 

 to be perfect ab initio; but about six years ago much discussion having taken 

 place as to the proper gauge, this decree was altered, and there is now no 

 limitation in the width of the gauge, which is left entirely to the discretion 

 of the engineer. Now, the consequence is, that although it would be de- 

 sirable that there should be a standard gauge fixed, yet, so divided have the 

 public been as to what is the right one, that we have at present no less than 

 seven different gauges used throughout the United Kingdom ; some of the 

 .Scotch lines, for instance, have a gauge of 4 ft. 6 in., and others of 5 ft. 6 in. 

 The Eastern Counties Company have adopted 5 ft. The gauge of the rail- 

 ways in Russia is 6 ft. On the recommendation of the Irish Railway Com- 

 missioners, the Belfast and Armagh Railway Company have made their 

 gauge 6 ft. 2 in. On the Great Western Railway the gauge is 7 ft. Now, 

 as much as 18 years ago, Mr. Tredgold, a celebrated and scientific engineer, 

 made the following observations : — " The width between the rails being de- 

 pendant on the height of the centre of gravity of the loaded carriage, and 

 this again varying witli the nature of the load and the velocity, it will be 

 obvious we cannot do better than make the breadth between the rails such, 

 that by disposal of the load, the centre of gravity may be kept within the 

 proper limit in cither species of vehicle, whether swift or slow, and it would 

 be desirable that the same breadth and the same stress on a wheel should 

 he adopted on all railways. We would propose 4 ft. 6 in. between the rails 

 fur heavy goods, and 6 ft. for lighter carriages to go at greater speed." 

 Now, it is remarkable that, during all the discussions that took place with 

 regard to the gauge, this observation was never referred to. M'hen Mr. 

 Brunei broke through that fixed number for the gauge, and adopted another, 

 he gave very Strong and sound reasons for so doing ; whether he was right 

 in assuming so high a number as seven is questioned b) many, but the prin- 

 ciple upon wliich he went was this—" I have (said he) laid out the line as 

 nearly level as possible ; the curves that I have adopted are nearly equivalent 

 to straight lines ; I keep the centre of gravity low, by placing the body of 

 the carriage within the wheels, and anticipating greater stability and steadi- 

 ness, I shall be able to go at a much higher speed, and with much more 

 assurance of safety." The Irish Commissioners argue thus — " From the 

 nature of the locomotive engine, its power is so great in proportion to the 

 friction it has to overcome, that it is capable of drawing a load which (even 

 with a greatly increased breadth as compared with common road carriages) 

 extends to a very considerable length, and, in order to reduce this length as 

 much as possible, it is necessary with the present breadth of way to make 

 the wheels run within the frame which supports the carriages; the seats of 

 the passengers are, therefore, placed above the periphery of the wheel, 

 which, for the sake of lowering the height of the centre of gravity, is made 

 as small as possible." 



One great theoretical objection, tlkerefore, to the narrow gauge, is the in- 

 creased friction consequent upon the reduction of the diameter of the wheel, 

 since besides what is due to the load, the friction of a wheel, at the axle, 

 may be said to depend upon the proportion of the diameter of the wheel to 

 the diameter of the axle ; but, in attempting to carry out this principle in 

 practice, the axle has sometimes been turned down so small as to produce 

 much greater and more positive inconveniences, and it is very questionable 

 if it be prudent or desirable to make the proportion between the wheel and 

 axle greater than 15 ta 1, and which proportion can be obtained with 3-feet 

 wheels. Now, with a 4-feet wheel and a 3-inch axle, tlie proportion being 

 16 to 1, it may be well doubted if, on this account alone, the large wheels 

 are worth their greatly increased ecst. The commissioners, however, urged 

 that the same carriage room may be preserved, by extending the breadth of 

 bearing of the rails, so as to allow the wheels to run outside the frame, in- 

 stead of running within it, in which case we can bring the body of the car- 



