312 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Oct. 



From the cnncliiding senlence of lliis quotation, it is clear lluit Mr_ 

 Bidder's only lest of the relative economy of the two engines is — not 

 which does the greatest quantity of work for a given quantity of coke — 

 but, which gets rid of the greatest quantity of water for a given quantity 

 of coke : and, accordingly, he has drawn up a tabular account of the ex- 

 periments, wherein, in the very cases in which the broad gauge engine 

 evidently did the most work with a pound of coke, he concludes that 

 because it did its work with a small quantity of water, therefore the engine 

 was comparatively ineconomic ! If the table «ere not actually printed 

 and published, our readers might perhaps doubt whether we had fairly 

 represented its conteuts. The following, however, is an exact copy : — 



The fifth column gives, according to Mr. Bidder's views, the flgures by 

 yhich the economy of the engines is to be tested. Let us take the first 

 experiment in each case. In the narrow gauge experiment, No. I, the 

 train was 50 tons, and the consumption of coke 3r2 lb. per mile; in the 

 broad gauge experiment the train was 80 tons, and the consumption of 

 coke 7iot 2!^\h. more per mile. It is obvious that the 21 lb. will not alone 

 account for the enormous difference between the two loads — namely 30 

 tons. The only conclusion which any rational unprejudiced man could 

 draw would be that more work was got out of the coke in the one case 

 than in the other. And this conclusion would be greatly conBrnied by 

 observing what Mr. Bidder omits mentioning, that the broad gauge train 

 moved fourteen miles an hour faster than the narrow gauge train. And 

 yet, because the water evaporated was less in one case than the other, we 

 are provided with a fifth column of " water evaporated per lb. of coke," 

 from which it is gravely iiiferred that the narrow gauge trip was performed 

 the most economically ! We must protest against this wholesale method 

 of jumping at conclusious which shows a lamentable confusion of ideas 

 respecting the mechanical action of steam 



We said that Mr. Bidder's own figures contradicted his hypothesis that 

 "the quantum of evaporation is a function of [i. e. is proportional to] the 

 number of blasts per minute." Taking Nos. I and 3 of the broad gauge 

 trips, which were respectively the slowest and fastest trips, the quantity 

 of water in the first case was the greatest (viz., 243 lb.) and in the second 

 the least (viz., 2321b.). We get precisely the same result with the fastest 

 and slowest of the narrow gauge journeys : so that if Mr. Biddei's table 

 prove any relation of the evaporation to the blast at all, the conclusion 

 must be the very reverse of his theory. It has been ascertained that if an 

 engine be deprived of its blast pipe, the rate of evaporation will be re- 

 duced to about one-fiflh ; but from the few experiments instituted under 

 this head, it would appear that uuder ordinary circumstances, when the 

 blast is in action, its effect on the rate of evaporation varies as the fourth 

 root of the velocity. 



Before concluding these observations, we ought to ofler some remarks 

 on the particular circumstances under which the narrow gauge experi- 

 ments were made. The following extracts from Mr. Gooch's report are 

 Dot a little surprising " The ensi'n- was on each occasion placed at Durliut;- 

 ton over a powerful stationurij blast for the purpose of getting xerij hot uater 

 in the tender and a bright fire to start with." 15y these means, the water 

 in the tender was raised to IhU". In the experiments witli goods trains, 

 " tlie engine teas placed over the blast, and remained there an hour and a 

 half. The tender containing warm water teas tuUcnfrom another engine and 

 attached to the regular tender, and men were prorided to bucket the icater 

 from one tender to another as the train uas moring." Mr. Gooch plain- 

 tively observes that this contrivance would have been of great use in the 

 broad gauge experiments. 



The love of philosophical accuracy displayed by the- conductors of the 

 narrow gauge experiments precludes the supposition that theij sanctioned 

 these devices, which must therefore be attributed to the subordinate ofiicers 

 of the railway. But, at all events, they suHiciently aecouut for the cir 

 tumstance that the narrow gauge engines got rid of more water for each 

 pound of coke (although they generally did less work for each pound of 

 foke) than the broad gauge engines. It is, of course, more easy in the 



dead of winter to boil water previously raised to a temperature of 180 

 than water originally at the temperature of the atmospliere. 



We must guard ourselves against the supposition that the experiments 

 prove decisively the superiority of the broad gauge engines. In fact, 

 they prove nothing. They were so few and so improperly conducted that 

 no trustworthy conclusion can be derived from them. They ought to have 

 been repeated several times over, under ihe superintendence of disinterested 

 persons, whose object was — not to get up a series of showy results — but 

 to exhibit, as nearly as possible, the ordinary working of either kind of 

 engines. However, the observations here made will have, at least, one 

 good elTect: they will enable the reader to appreciate the philosophy givea 

 in evidence before public commissions o i engineering questions, and to 

 estimate the value of the experiments authoritatively sanctioned. 



ON MASONRY. 



[From the F.cclesiologist.) 



The writer of this paper remembers an incident which puis in a rather 

 striking light a very puzzling questiou about masonry, that must have often 

 occurred to some or <itlier of our readers. He had just been shown some 

 of the famous quarrie.^ near Caen, by one of the proprietors ; and having 

 come out near a little Norman church, claimed his conduclor's admiratiou 

 for the effect of solid strength and lasliogness w hirh Romane.-que ashlar, 

 particularly when of Caen stone with the hoar> grey of suven centuries 

 upon it, always presents.* The answer was not what he expected. In- 

 stead of joining in his praises, his guide began to lament that the ancients 

 could not do better, because Ihey could not draw stones of any consider- 

 able size from Ihe quarries. They had made good use, he allowed, of the 

 small broken bits of stone they could dig out ; but our mechanical advan- 

 tages enabled us, willi larger blocks, to adopt a more perfect kind of ma- 

 sonry. Now it is difficult to answer this. There is no doubt that some of 

 the finest buildings of antiquity are constructed of stones of immense size. 

 The Pantheon may be quoted for this ; and every one will remember the 

 huge blocks that must have been quarried for monolith columns. The 

 general declme of art shows itself in this respect perhaps as well as 

 others. There is a great gap between such a building as the Porta Nigra 

 of Treves, and the best of early jiomanesque masonry. Art in all its 

 branches was, it seems, almost to die: in order perhaps that Christian .\rt 

 might be less a development than a new creation. The Pharos in Dover 

 castle is a fine specimen of Koman excellence : iis builders could not get 

 hewn stone ; hut they so bound their flint rubble with bands of brick, that 

 the tower stands like a rock. Close by is the desecrated church with a 

 good deal of undoubted British masonry in its shell. Here too, there is 

 '' Uoman brick" in tiie qn:ilus, &:c. ; but the general inferiority of tlie ma- 

 sonry to the real Kiiman Hork is very sinking. Then, again, the fine Ro- 

 manesque ashlar in the chapel of the Norman keep in Ihe same fortress, is 

 a specimen of the reviving art of masonry ; but it is in kind like that of 

 the little parish church near the Caen quarries. t The stones are all small, 

 tliough beautifully and effectively used : there is no single slone to tempt 

 you to measure its length and width, and to exclaim at its bulk : which 

 seems to be the general ellect produced on people's minds by modern ma- 

 sonry. As a mailer of fact, it must, we suppose, be granted, that the ar- 

 chitects of the Romanesque and Early-Poinled slyles could not procure 

 large stones : they were compelled to use even line building stone, like 

 that (which they so highly valued) of Normandy, in small masses, as they 

 could iuartilicially oblaiii it from the quarries. So late as 1841 there was 

 not a single crane at Caen, by which to ship the slone, had it been extract- 

 ed in very large blocks, — a fact that may assist us to comprehend the great 

 mechanical disadvantages under which the lUKlia-val architects laboured. 

 But though their stone was in such small pieces, how beautifully they 

 used it ! Of course, there is a great deal of ancient work that is very 

 bad ; although m hat has stood for six or seven centuries, may seem fairly 

 eniitled to enliie exemption from any blame. But as a general rule, early 

 nia.sonry — at least after Ihe later Romanesque liad superseded the Anflo- 

 Saxon kind — is surprisingly excellent : not only for solidity, but for keep- 

 ing and harmony. It suits the stjle. The eye is saiisfied entirely, wilhout 

 knowing or inquiring why. You admire the design, and feel almost un- 

 consciously that it IS worthily embodied in its material exhibitum. ^ uu 

 are neither induced to examine and commend the ingenuity wilh which the 

 difliculiies of a bad building stone are overcome, nor are you called on In 

 join in the vulgar admiration of " such big blocks." lu a word, you for- 

 get such a mere detail in the whole : but when jou can descend I'roin the 

 whole into particulars, you find ihem all that can be wished. 



There is so much that might be said about masonry, that we are unwil- 

 ling to open the subject from a consciousness of our owu ignorance. No 



* Ttiis efi'ect may be partly judged of from an examination of the drawings of Than 

 church, in the elder Pugiu's '■ Normandy." 



t Nut nearly eiidugh attention has been paid to the subject of masonry, if only tn de- 

 termine dates. Let any one compare the excellent asiilar of lliis cliapel, und the wretched 

 rublle of St. Seimlchre's Cuinljridwe, which is later in pLiiut of age; or even \vilh the 

 White Chapel iu the Tower of London. 



