170 



THE CTA^IL ENGINEER AND .VRCHITECTS JOURNAL. 



[May. 



of Commons, tliat the Sniitlianiiitou Itaihvay Section, of twenty feet to the 

 mile, was as inactically good as tliat of tlie Great M'estern, wbicli was on a 

 (lead level, lie had made that assertion on the ground that iu tlie descent 

 tliere would he as nuieh advantage gained as disadvantage to he encountered 

 iii the ascent ; and, excejit tlie inconvenience which would result from the 

 inequality of speed, heing at one time fast and at another time slow, there 

 would he no otlier inconvenience or disadvantage worth mentioning. And, 

 therefore, he did inntend that it was an extremely improvident .and unwise 

 expenditure to lavish millions in cutting through elevations and filling up 

 valleys hy lorgo euil)ankments, and constructing tunnels and viaducts, and 

 all tlie other cx|)cnsive works, to ohtaiu a dead level. Evperiments had 

 since heen made which jiroved the conclusions he had arrived at to he suh- 

 stanvially correct. These ex[)eriments had heen made hy Mr. Wood, the en- 

 gineer of the Liverpool and .Manchester Railway, on the Grand Junction Line. 

 A train of twelve carriages, each weighing five tons, was attached to the 

 lJei-/ii engine, the gross load heiiig ahoiit ii2 tons. This was started from 

 Liverpool to Birmingham, under peculiarly favourahlc circumstanres as re- 

 garded the calmness of the day and the state of the weather, the engine 

 heing allowed ta do its own work, unassisted on the various inclines ; the 

 velocity of speed throughout the whole way from Liverpool to Birmingham 

 and hack again fr.im Birmingham to Liverpool, was, of course, accurately as- 

 certained, and if the theory which he had endeavoured to develop was cor- 

 rect, they ought to find that the average speed in ascending and descending 

 the inclinations would he nearly equal to the sjieed they ohtained on the 

 level parts of tlie line. There were several jilaucs along the line, and taking 

 the steepest tirst, viz. 1 in 177, they ascrnded that plane at the uniform 

 velocity of 22} miles an hour, and descended it at the rate of Hi miles an 

 hour, the average heiug as nearly as possihle 31eJ- in ascending and descend- 

 ing. The ascent and descent of the other gradients on the hne gave the 

 same, or very neaily the same, results — the average speed varying little from 

 ■jl miles an hour. There was a cousiderahle portion of the line level, and 

 tlie speed iqiou that portion was 31 miles, heing just the same, allowing for 

 inevitahle small discrepancies, as the average speed upon the inclines up and 

 down the line. The plain inference which Dr. Lardner drew from these ex- 

 jieriments was this: that the trains hctween Liverpool and iiinniiigliain ]ier- 

 fonned their journeys in just as short a time as they would do if the line 

 was a dead level from terminus to terminus. He, therefore, considered it 

 unadvisahle to expend money in attaining very fiat sections, gradients not 

 exceeding thirty feet a mile heing, iu his opiuion, practically as good as a flat 

 and dead level. 



Dr. Lardner next ohserved that it was inexpedient to lavish money in 

 avoiding curves of a less radius than a mile, as no danger could, he helieved, 

 attend a curve having a raihus of half a mile, perhaps less. It was, likewise, 

 apparent that it was useless to lavish cajiital on expedients for greatly di- 

 minishing friction ; such, for instance, as the adoption of wheels of a large 

 diameter, for it was clear that friction afforded hut an insignificant p.art of 

 the sources of resistance, while, by increasing the bulk of the carriage, they 

 gave a greater frontage, and increased the resistance from other causes. 

 Further, observed Dr. Lardner, it seemed probable that they should not with 

 practical trains attain, in the present state of mechanical science, those ex- 

 traordinary s])eeds which they were accustomed to hope for some time since. 

 It was not at all likely that they should ever move at the rate of a hundred 

 miles an hour, for the resistance due to the velocity would increase iu so 

 enormous a proportion, that it would become an opponent too formidable for 

 any available power to overcome ; still less was it likely that those speeds 

 would ever he ohtained with profit. Upon this subject Dr. Lardner remarked, 

 " In some exiierience of railway travelling, I have never witnessed a speed 

 exceeding '15 miles an hour; I did once accomplish that speed with four 

 coaches, hut only for a short distance. Jlr. Woods has told me, that he has 

 himself gone 48 miles an lioiir; hut that was not for any considerable dis- 

 tance. Let it he remembered, that great speed might he attained in this 

 way. You may get an engine with plenty of steam ; you may screw the 

 safety-valve down so as to get a surcharge of steain ; you may ]mt no load 

 on the engine, so as to diminish the resistance ; and you may run it down a 

 gradually declining gradient till you exhaust all the steam in her boiler upon 

 a falling gradient. Then, if all these things be done, if the rails be clean, 

 and if a correct account he ke]it, then there will he no denying that great 

 speed has been attained. But when we s|ie.ik of great speeds, this experi- 

 ment, the whole length of the thaiid Junction Railway and back, at the axe- 

 rage rate of .'51 miles an hour tluough the whole distance, with twelve 

 coaches, was a very respectable performance indeed, iu the present state of 

 locomotive power." 



LECTuau IV. 



Dr. Lardner said there were two prliici])les on which railways were gene- 

 rally constructed : — First, by departing as little an possible from the natural 

 surface of the ground, and distributing the inclinations very generally and 

 evenly over the whole length of the line, in which case such power was given 

 to the engine as to make it pull up the requisite loads with requisite speed. 

 Others, on the eoutiary, proceeded on the principle of concentration, and in- 

 stead of distributing the inclinations over the entire length, they threw them 

 all into one place, as in the ease of the Whistou and Sutton planes on the 

 Liverpool and Manchester Railway, and it followed, as a uccessai-j' eonse- 

 queoce, that the engines which were adajited for working the greater part of 



such lines nearly ou a level, could not easily draw the loads up the inclina- 

 tion, which must therefore be done hy additional engines ; hut if it had been 

 expedient to make the whole line with inclinations like those of the Wliiston 

 and Sutton jilauex, there xvonid not have been the least difiiculty in working 

 it, and those planes would have heen ascended with just as much speed as that 

 part of the line was now traversed which was nearly level. 



Dr. Larihier next iiroceeded to consider the source of the jiower of the en- 

 gine, tlie niauuer iu which it was produced, and the mode in which it was 

 adapted to uac. They should naturally suppose that an eleriient in eiigiue- 

 niaking of such vital importance as the (luantity of surface which ought to he 

 pro\ided to receive the action of lire, in order to produce a given tpiantity of 

 evaporation, ought to be known to engineers, but they would probably he sur- 

 prised to find that even the best engineers were as ignoiant of it as themstdves. 

 No two of them could .tgree, and they ilitfered, not only in small quantities, 

 hut even as much as 100 per cent. Anolhcr thing of iinportanee was the 

 magnituile of the grate. Sn:iie held, that a sijuare foot of grate per horse 

 liowcr was siifhcient ; some allowed more, and some less ; hut generally 

 speaking, three quarters of a square foot was allowed. In the ajiplieation of 

 fuel there was also eonsideralile dilferenee. It might he applied so as to pro- 

 duce considerable effect, or so as produce comparatively little etfect. In this 

 consisted what was called the art of stoking; and iu no place was this worse 

 done, in no place did it need to be better done, than on board sliips. The 

 coals should be spread lightly upon the grate ; and when in a state of incan- 

 descence, the stoker should |uish it back, and lay on more coals. The first 

 effect would he, that the coals first laid ou woidd be coked. The heat would 

 be so great that the gaseous jtart would be expelled. These gases would be 

 impelled forward by the draught; and as the}' passed the incandescent coal, 

 they would he consumed, and no smoke would issue from the chimney, the 

 smoke heing the nnconsumed part of the fuel. As soon as the coke at the 

 hack was consumed, the stoker should ]msh back that in the front, and in- 

 troduce a further quantity of fuel. This would make a common furnace, in 

 fact a smoke-consuming furnafe, and there would be a uniform evaporation 

 of steam. But was this the iiractice observed ? By no means. Neither in 

 marine boilers imr in land boilers had the stoker any idea of taking any such 

 pains ; he adopted not the most ethcient way, but the way most comfortable 

 to himself. He jiroceeded in this way : he let the fire in the grate be nearly 

 out, he then put in an enormous quantity of coal ; the consequence was, the 

 very instant this was laid on, there issued an enormous quantity of smoke, 

 which might he frequently seen issuing from the chimney of a steam-boat. 

 That went on for some time, till at length the chimney got a little rest. This 

 was nothing more than the effect of putting on fresh fuel ; and the smoke 

 continued till it was burned red, and it suited the stoker's [ileuMire and con- 

 venience to open the grate again. In some of the bcH conducted government 

 vessels this was not allowed. They paid their stokers sufHeient wages, and 

 made them do their work ; and on the Meden, for instance, there was no 

 smoke from the cliimuey at all. There was nothing new in this. Mr. Watt 

 jiroposed it ; and in his factory at Soho, smoke was never seen issuing from 

 the chimney. The only effectual remedy which could be devised would be to 

 feetl the furnace by self-acting grates. One had been invented in wdiich the 

 grate was made circular, and it revolved. The feed of coal was placed in a 

 hopper, and the coal passed through it like a funnel. The coal was put in 

 that part of the grate furthest from the flue. This machine was kept in mo- 

 tion by the engine itself, so that to a furnace of this kind there was little ne- 

 cessity for the attendance of men at tdl.—Miillnml Cunii/ie.s' lleralil. 



THE FRENCH HISTORICAL COMMISSION. 



CEj:tracledfi-om the Geutleiiian's Magazine fur February, 1810.J 



Tun Report on the labours of the Committee of Arts and Monuments is so 

 extremely interesting, that, were it not too long, we should be inclined to 

 translate the whole. The object of this Committee is not only to publish a 

 complete survey of the monumental antiquities of France, hut also to provide 

 for the preservation of the monuments themselves. A series of printed ques- 

 tions is sent to every parish throughout the kingdom, in order to obtain the 

 primary information to regulate the proceedings of the Committee in this 

 survey. The undertaking will require many years, and much money. Those 

 districts and inonuiucnts will be taken first in order which are of the greatest 

 interest, or are most important in their character, or which are in the greatest 

 danger of perishing ; for the Committee has established it as a rule, that an 

 edifice which is threatened with ruin shall always be preferred to a monument 

 which is in a good state of preservation. .Vt lu'cscntthis Committee is occu- 

 pied in the publication of specimens or models of the lUffereiit forms which 

 its labours will take. These are to he, 1, the complete survey in description 

 and delineation of the cathedral of Noyon, as a specimen of severe ecclesias- 

 tical architecture, and, 2, of that of Chartres, as being the most extensive and 

 superb ecclesiastical edifice in France ; 3, the Roman, Merovingian, and Car- 

 lovingian antiquities of I'aris, as a specimen of the mode in which the great 

 towns will be treated; 1, the description of the arrondissement of Rhcims, as 

 a model of the monumentiil st.atistics of the provinces. 



" The mission of the Committee is, in fact, to search noire France monn- 

 inenlale ; to catalogue, describe, and delineate all the objects of art scattered 

 over our soil ; to draw up an archaeological register, so succinct that the 



