1848.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



67 



together intolerable ;" which is as much as to say, that instead of 

 suggesting the idea of strength and perfect security, ^he arch 

 loolis unequal to the due support of the columns. Nevertheless, 

 it is certain that those arches are capable of safely bearing the 

 weight of the columns, and can also safely bear the weight of 

 what is much heavier still — namely, Allan's own leaden criticism. 



V^III. Very great pity is it that St. Martin's Church stands just 

 where it does, because it was in consequence allowed to interfere 

 very injuriously both with the National Gallery and Trafalgar 

 Square. Owing to its being obstinately insisted upon as a sine qua 

 non, that the portico of the church should be exposed to ^iew from 

 Pall-Mall-East, the front of the Gallery was obliged to be set fur- 

 ther back than it otherwise needed to be, and the site of the 

 building — at best a very cramped-up one in its rear — consider- 

 ably reduced in depth ; in some parts, to little more than half. 

 Hence, the interior of the structure does not at all realise 

 the promise made by its extent of fa?ade. Admitted it must be, 

 that the arcliitect did not economise what space he had so well as 

 he might hdve done ; still, that does not excuse those whose 

 capricious whims thrust difficulties upon him where, without such 

 addition of them, there were many to contend with. — On the other 

 hand, as regards the " Square," its symmetry and rectangularity 

 have been sacrificed for the sake of keeping its east side in a line 

 witli the portico of St. Martin's, which would still have shown 

 itself, even had it not been made to come actually into that corner 

 of it. After all, does the church display itself to such advantage, 

 as to reconcile us to the inconveniences and deformities which it 

 has been allowed to give rise to ? The reply will be : " Hardly." 

 Thrown open to view from such a distance as it now is, that por- 

 tico is not so impressively striking as it formerly was. As it stood 

 originally, the situation seemed altogether unworthy of it, owing 

 to its being much too confined, and to the meanness of the houses 

 hudtUed-up round the church — a species of contrast more pictu- 

 resque than becoming or agreeable. Nevertheless, as it was then 

 seen, the portico showed imposingly ; and all the more so, because 

 the view was confined nearly to that — the steeple not being seen 

 unless it was directly looked up to ; whereas now, as seen from a 

 distance, the entire structure, that is, both portico and steeple — 

 the latter of them anything but a graceful and well-composed 

 object of its kind — are seen together ; owing to which, the portico 

 loses considerably, and the classical character that would else stamp 

 it, when beheld at such a distance that only its exterior or columns 

 are visible, is greatly interfered with, if not altogether forfeited, 

 by the uncouth appendage which rises up immediately behind it. 

 By no means is the view of the portico from Pall-Mall-East a pre- 

 possessing one. — Trafalgar Square itself falls very far short of 

 what was only reasonable expectation for it. Strange perversity 

 of judgment, bungling, and disregard of architectural disposition 

 have been allowed to manifest themselves in it. Although the 

 area itself seems to have been expressly planned for the reception 

 of the Nelson monument, the column is, after all, not placed 

 within it, but is pushed just out of it. The only assignable reason 

 for such dovenright preposterousness is, that had it been erected in 

 the centre of the area prepared for it, so lofty an object put just 

 there would have had an unfavourable effect upon the front of the 

 Gallery. Very true ; but then that consideration ought to have 

 been a raison de. plus, and an all-sufficient reason in itself, for not 

 adopting a column, more especialy as there was another thing of 

 tlie same kind just by. 'There were many other designs which, 

 besides being sufficiently well adapted to the situation, were far 

 more original and artistic. It was, therefore, to be presumed that 

 the secoud competition was for the pui-pose of enabling the com- 

 mittee to retrieve the error of their first choice ; when lo ! to the 

 amazement of every one, the result was just the same as before, — 

 which was only making matters worse than before. Far better — 

 far more honest and honourable would it have been to have abided 

 by their decision, than to make such show of intending to retract 

 it. The least they could in decency have done, would have been to 

 justify by some show of reason for it, a choice so strangly persisted 

 in, and so strangely acquiesced in by those who had been trifled 

 with. The best that can be said of the humdrum Nelson monu- 

 ment is that it serves to render the facade of the National Gallery 

 perfectly satisfactory in comparison with it. 



RAILWAY SECTIONS IN SIDELONG GROUND. 



On Tables for Setting out the Width of Cuttings and Embankments 

 on Sidelong Ground ; and also Formulce for Computing the Area of 

 Vertical Section. 



By R. G. CL.iRK, C.E. 



The object of this paper is to investigate some simple formula?, 

 and from thence to construct some tables, to enable the assistant 

 engineer or contractor to set out the widths of cuttings and em- 

 bankments on sidelong ground; and also to calculate the solid 

 content of any portion of the ground. The subject may be re- 

 solved in the following proposition: — 



Given the / of inclination of ground, the depth (from field- 

 book, &c.) of ground to the centre of balance or formation level, 

 and tlie ratio of the slopes ; to determine where they will meet the 

 ground at surface. 



Let HAFBD (fig. 1) be a vertical section of the ground; 

 A B the formation line, represented by 2 i ; the given angle of in- 

 clination of ground H D with the horizon by e ; tlie given depth 

 O F from the stake O perpendicular to centre of formation level 

 denoted by a. 



F B 



Fig. i. 



I. We will proceed first to determine a formula for O D Let it 

 be. r; draw DK perpendicular to A B produced ; O /' parallel to 

 A B K Let D B be the given slope m base to 1 perpendicular ; 

 draw the vertical B C. 



Let D/= y; then Oc = FB = 6; ef= my; also by similar 

 triangles, C e ;= m a. .■■Of=b + ma + mg. 

 Now, by triangle O/D, right-angled at/, we have 

 I : x :: sin e : y. .■ .g =:x.sia0. 

 Again, 1 : x :\ cos e : b + 7na + my. 



. -.x. cose =z b -{■ ma -\- my. 

 Eliminating y, then x (cos e - msiae) = b + ma ; 

 b -\- ma 



therefore, a? = 

 1 



(1) 



of the above formula, the Table 



From the factor, — 



cos 8 — m sin f 



No. I. is computed from 5° to 20°. 



2. To find an expression for O H measured from O on the 

 descent. 



Draw H M (fig. 2) perpendicular to A B produced. Let H A be 



Fig. 2. 



the given slope, ratio as before. Let H M = ?/' ; then will A M =: 



m y'. Therefore, H G = N F = 6 -(- nj «/' ; also O g ^ a — y'. 



By the triangle H ^r O we have 1 '. jc' W sin B ; a - y' ; 



therefore, a - j/' := a;' . sin e ; and ^' = a — j' . sin B. 



Again, 1 x' : ; cos 9 ; b -\- m y'. 



Eliminating y, we have x' (cos fl -J- m sin e) ■= b -\- ma; 



therefore, x' = ^4- ; — (2) 



cos B -)- m sin fl 



From this expression, Table No. II. is calculated by the factor 



1 



cos e -|- TO sin fl' 



10* 



