1843.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



31 



New Locomotive Engine — 'The Man of Kent." — Messrs. Rennie 

 have turned out another locomotive that promises to excel the " Satellite," 

 sent out by the same firm about 12 months since, and which has been work- 

 ing on the Brighton Railway with so much satisfaction and economy, the 

 average consumption of coke being not more than 20 lbs. per mile, with a 

 train of eight or nine carriages. It lately performed the distance from 

 Croydon to Brighjpn, 40i miles, with six carriages, in 52 minutes, including 

 three stoppages of three minutes each, which deducted, make the actual time 

 running only 43 minutes. During the whole period of 12 months it has 

 been running not one shilling has been laid out for repairs. " The Man of 

 Kent" promises even to excel these excellent qualities of the " Satellite ;" 

 it is a splendid specimen of engineering work, and possesses several im- 

 provements ; among others is an important one of encasing the cylinders, 

 which are 15 inches diameter, with a jacket, which will always be kept 

 charged with hot steam ; a second improvement, is the introduction of a 

 damper, so constructed, that the apertures of the tubes next the smoke-box 

 may be wholly or partially eclipsed simply by the driver turning a handle, 

 which regulates the draft of the engine to the greatest nicety ; a third 

 improvement is in the regulator, which is generally circular consequently diffi- 

 cult to keep tight — it is now a slide valve. The centre of gravity is kept 

 down by the spring being below instead of above the axles, as usual. We 

 hope next month to be able to give some account of its performance. 



South Eastern Railway Works. — The stupendous works now pro- 

 ceeding for the formation of the South Eastern Railway between Dover and 

 Folkstone are rapidly progressing, and exteusive preparations are making to 

 throw down a large portion of Rounddown cliff, just beyond the Shakespeare 

 tunnel, to make way for the sea wall. During last month experiments were 

 made by the miners below the cliffs, under the superintendence of Lieut. 

 Hutchinson, and General I'asley is expected to be present at the grand ope- 

 ration ; this blast is to be effected by the enormous charge of 18,000 lbs. of 

 gunpowder; it will be exploded by the electric spark from a galvanic bat- 

 tery, carried by conductors 1,000 yards in length. The experiments have 

 hitherto been quite satisfactory, and it is expected at once to dislodge a por- 

 tion of the cliff many tens of thousands of tons in weight. 



Comparative Cost of English and Foreign Railways. — In Mr. 

 Robert Stephenson's elaborate and important report, addressed to the direc- 

 tors of the South Eastern Railway, on the system of railways, as now pro- 

 jected by the French government, he gives an analysis of the cost of rail- 

 ways in England, selecting three lines — the Northern and Eastern, the York 

 and North Midland, and the Birmingham and Derby— as cases similar in 

 their results to those in France now under consideration ; from this, and also 

 an analysis of the cost both of the Belgian and French lines, it appears the 

 average cost per mile of the English lines is 25,450/., the French lines, 

 23,000?., and the Belgian lines, 16,206/.; thus showing a difference in the 

 cost in favour of the Belgian lines over the English of no less a sum than 

 9,244/. per mile, and over the French of 0,794/. 



Burning Lens worked by the Drummond or Oxy-Hydrogen 

 Light. — A colossal burning lens, three feet in diameter, and weighing 5 cwt., 

 has been erected in the Royal Adelaide Gallery, intended to be worked by 

 the Drummond, or oxy-hydrogen light. Some private experiments of this 

 power of the Drum mond light have taken place, when it was found that the bulb 

 of a differential thermometer introduced into the focus, at a distance of 16 ft., 

 was sensibly affected, and a piece of phosphorus introduced in the same 

 point was fused. It has long been asserted that the heat accompanying 

 light obtained by artificial means does not produce heat capable of being 

 transmitted and concentrated through lenses ; these experiments fully prove 

 the contrary. 



Price of Gas. — Gas is manufactured in Manchester by the Commis- 

 sioners of Police, and though sold at from 5s. to 6s. the 1,000 cubic feet, 

 yields a revenue of 12,000/., or 15,000/. per annum to the town. The large 

 consumers pay 5s. the 1,000 feet. [In Dublin the charge, when burnt by 

 meter, is 10s. the 1,000 feet, and the quality so inferior in illuminating 

 power, as to require the holes in the burners to be about double the ordinary 

 size. If our civic authorities would follow the example of the Manchester 

 Commissioners, it might prevent the necessity for a burgh rate, and confer a 

 boon on the gas consumers.] — Dublin Advertiser. 



An Immense Block of Granite has been landed at Mr. Tuckvill's 

 wharf, Greenwich ; it is from the llaytor Company's quarries, Dartmoor ; 

 measuring 10 feet 6 inches square, and weighs 22 tons. It is to be used as 

 a covering for a mausoleum in Kensal-green Cemetery. 



Bi.i.l Rock Lighthouse. — During the lale heavy gales which have done 

 so much damage to shipping, particularly between the 19th and 23rd of 

 October, the sea sprays appear, by the monthly returns from the Bell Rock 

 Lighthouse, tc have risen upon the building to ihe height of from 60 to 90 

 feet every tide. M bile this heavy sea ran, one of those great detached masses 

 of stone familiar to the lightkeepers by the name of " Travellers " was forced 

 across the rugged surface of the rock, about 100 yards to the lighthouse, 

 where it deslroyed part of the cast-iron landing wharf. This stone measured 

 about 7 feet in length, 31 teet in breadth, 2i feet in thickness, and must have 

 weighed about 4 tons. To prevent mischief by the movement of these great 

 stones, Ihe lightkeepers are provided with quarry tools, with which they 

 brc l;e it up and arrested ils progress, but it was no easy task from the run of 

 the sea. The heaviest seas which visit Ihe Bell Ruck are from the North- 

 east, but the present gale was chiefly from the North west ; and ii is not a 

 little remarkable that the Frith of Forth was but little affected during (his 

 storm above the Island of May. 



Quarrying Stones.— Another remarkable example of the contributions ol 

 science to the arts of life is derived from the properties of 1,- 

 in the tast to quarrying blocks of stone, when the object is I i i 



blocks from the surrounding m is i. A groove is rut some 2 Inches In depth in 

 the required direction: this done, the groove is filled with lit, I 

 lighted until the rock is highly heated. The rock then is, of course, ex- 

 panded by the action of the heat; the fuel is then swcpl i 

 water ■immediately poured into the gro v e The sudden contraction causes 

 the block instantly to split oil. The same principle is daily exhibited on our 

 tables. If a heated glass be suddenly filled with cold water, it inline 

 breaks in pieces. In this way blocks SO ft. long and ii thick are easily taken 

 off with no other labour than that of chiselling mil the gri ove. A 

 example ot the application of science to the economy of power is 

 in France in the quarrying of millstones. They are required, as you are well 

 aware, to he circular ami flat— cylinders with a very small altitude compared 

 with the diameter— and the stone from which they are made is exceeding!) 

 hard. The mode of quarrying them is this :— A very high circular column 

 of stone is wrought out of the requisite diameter. To slice oil porl 

 this, such as are required by the common s'one saw, would he a v 

 immense labour, a quite different agent is employed. At regular successive 

 distances grooves are cut around the column, into which arc driven dry- 

 wooden wedges at evening, The dew which falls during the nighl being ab- 

 sorbed by the wood, causes it to expand with a power so irresistible, that 

 all the stones are found properly cracked off in the morning. —Dr. L\kdnek- 

 lectures in the United Slides. 



Seyssei. Asphalts. — Many of our readers, may remember that some years 

 ago, and previously to the introduction of asphalte into this country, we 

 expressed our admiration of the pavement, composed of that substanci in 

 Paris, and especially of that in the Place de la Concorde, the whole of which 

 has been long since paved with asphalte. It now behoves us lo point out the 

 piece of Seyssei asphalte laid down in April, 1838, in Whitehall, opposite 

 the Horse Guards, as equal to the pavement in the Phce de la Concorde, 

 or in any part of Paris, and considering that its thickness is only half an 

 inch, its having so long stood the traffic of so great a thoroughfare without 

 any apparent change, except a greater smoothness of surface, is very re- 

 markable. — Times. 



NOTICES ON THE STEAM ENGINE, Sec., IN REPLY TO 

 CORRESPONDENTS. 



We have been requested to correct certain alleged errors in our review 

 of the Appendix E, F, to Tredgold, given last month. In reference to the 

 engines of the Dee and Solway, a Greenock correspondent says — " The air- 

 pump rods are cased with gun metal, and the iron at the lower end is secured 

 by a brass flange jointed and screwed to the bucket, so that no part of the 

 iron is exposed to corrosion from the salt water. The upper and under 

 portions of the D valves are connected with three rods. (Is the writer of 

 that article aware that Maudslays have only one rod in the engines of the 

 " Great Western ") The holding down bolts were made as requested by the 

 engineer appointed to inspect the engines." 



Our readers will probably recollect that our objection to the air-pump 

 rods of these engines was, that they were cased at all. We have known 

 instances in which this casing stripped off, and have been informed that some 

 such accident did actually occur to the engines of the Dee or Solway. The 

 expedient referred to by our correspondent, of covering up the end of the 

 rod with a brass flange will, we fear, go but a little way in obviating the cor- 

 rosion to which we adverted, for it is not at the extreme end of the rod, but 

 at the neck of the rod, where any injurious corrosion takes place. The 

 water insinuates itself to a certain depth between the brass of the bucket- 

 eye and the iron of the rod, and eats its way up beneath the casing. We 

 have known air-pump rods to be rendered unserviceable by this species of 

 corrosion, when their extreme ends were comparatively uninjured. 



The allusion to the practice of Messrs. Maudslay is, we suppose, intended 

 to show that our strictures were shallow and hypercritical, t'pon this point 

 we shall leave our readers to form their own opinions, and shall content our- 

 selves with expressing our gratification that Messrs. Scott and Sinclair have 

 relinquished their old system in favour of that which we have all along 

 recommended. It forms no part of our function to inquire at whose instance 

 the holding down bolts, or any other part of an engine have been constructed 

 in an objectionable manner ; our purpose is not to find fault with any one par- 

 ticular party, but merely to express our conviction that certain practices are 

 bad, and ought to be exploded. We war not with individuals but witli 

 errors. 



Another Greenock correspondent informs us that the formula 



45 ( i — g J given in the notes on " Steam Navigation " in our last 



month's number has been " altogether misapplied." because, indeed, we have 

 alleged it to express " the rise or fall in temperature due to compression or 

 rarefaction, without reference to initial density." Our correspondent favours 

 us with an algebraic formula to prove his position, but our pages do not 

 contain the allegation he charges upon them, we, therefore, think it needless 

 to give the paper an insertion. 



