294 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[September, 



Nos. 1 and 3 were trnssed conformaWy to plate 39 of Nicliolson's Car- 

 penter's New Guide, the former being a model of a girder of 34, and the 

 latter of 25 ft. span. 



No. 1 was a i/neen bolt truss, of three pieces ; No. 3 was a iinr/ bolt truss 

 of iii-o pieces, similar to Fig. 3, and the weights were applied in the centre, 

 or over the angular point of the latter truss, and midway between the queen 

 bolts of the fornfcr. 



Hence it appears that whilst the queen holt truss, No. 1, was actually 

 weaker than the untrussed stick No. 2, the king bolt truss No. 3 was Z3 per 

 cent, sfrovger than the untrussed stick No. 4, of the same dimensions, and 

 similarly strained. 



Our experiments on model No. 5, which was trussed nearly in the same 

 manner ar Barlow's No. 3, display an augmentation of 35 per cent, over that 

 of an untrussed beam. 



The close agreement of our results with those of Barlow, probably justifies 

 the declaration that — at least whilst they are new — the common wooden king 

 holt trusses add one-third to the strength of the girders to which they are 

 applied. 



Tredgold, however, in his invaluable treatise upon Carpentry, (2nd. Ed., 

 London, 1828, p. 79,) says that " The methods in general adopted (for 

 trussing girders) have the appearance of much ingenuity, but in reality they 

 are of very little use." And again—" The defects of ordinary trussed girders 

 are very apparent in old ones, as it is not simply strength that is required, 

 but the power of resisting the unceasing concvissions of a straining force, 

 capable of producing a permanent derangement in a small surface at every 

 impression." 



As the tendency of time is undoubtedly to impair the efficiency of all sorts of 

 trussing, and especially of those which — like girders trussed within their own 



depth have rery obtuse supporting angles; more extended experiments and 



farther observations are necessary to settle definitively the question of strength, 

 between beams trussed within themselves %vith timber, and plain sticks of the 

 same bearing, and scantling. 



In 1828, Mr. J. Conder, soon after applying in practice the suspension 

 truss of tu'o angular points, (see Fig. 1,) seems to have become satisfied that 

 it was defective ; for he soon brought forward, as a great improvement, the 

 idea of forming the truss with but one angular point, like Fig. 3, inverted ; 

 and it will be remembered, that in our experiments we were unable to procure 

 any benefit from the suspension truss, until by the central bearing plate at a. 

 Fig. 1, we had, in effect, reduced that truss to one of a single angular point. 

 In trussing a girder, the main object is to strengthen the weakest point— 

 -which is the centre of the beam— and as Barlow's experiments upon direct 

 gueen bolt trusses, and our own upon inverted or suspension trusses, of two 

 angular points, indicated that no advantage was derived from either, when 

 strained in the middle, we are strongly disposed to conclude, that whether 

 the truss acts by tension or by compression, it should (in most cases) Itave 

 but one angular point. 



In support of this view, the writer may state that he has seen a uumber 

 of suspension trusses of two angular points— attached to the girders of 

 bridges— which, on close examination, indicated that they bore but little 

 strain ; whilst those with but one angular point, which he has had an oppor- 

 tunity of examining, seemed, in most cases, to be acting with much greater 

 efficiency ; this matter, therefore, seems to be of sufficient importance to 

 justify our soliciting to it the attention and consideration of professional 

 men. 



Philadelphia, April 28M, 1842. 



St. Rnllox Oi/mnft/.— This chimney is now finished. This e.-ctraordinary 

 work was construclccl under the superintendence of Mr. Andrew Thomson, 

 the able engineer. The extreme height, from the ground to the copesfone, is 

 450 ft. ; and, rising from a base forming the highest t^ble-Iand of the city, 

 the stalk is seen from a great distance in the surrounding country. In relative 

 height, indeprndent of the elevation of its base, it is little inferior to the 

 lofliesi superstructures in the world ; in absolute height, it towers into the 

 air incomparably higher. The great pyramid, Clieops, rises 498 ft., but this 

 includes a base of 150. The Strashurgli Cathedral is 474; St. Peter's, in 

 Eome, from ground to pinnacle, 450, being exactly the aililude of the monstrc 

 chimney ; St. Paul's, in Lonilon,370. Tlic base of the chimney under ground 

 is 4G ft. in diameter ; at the ground 40 ; and at the top 13 ft. 6 in. 



THE ROYAL ACADEMY'S TREATMENT OF 

 ARCHITECTURE. 



Sir — Neitlier "The Architect" nor "Ego Quoque" is, I suspect, 

 tlie only one, by a very great many, who have cause to be dissatisfied 

 with the manner in vvliicli architectural drawings are treated and dis- 

 posed of by the Hanging Committee of the Royal Academy — to say 

 nothing of the dissatisfaction given to those who go to look at, as well 

 as to those who send, subjects of that class. Now, though I do not 

 pretend to be able to suggest any " reasonable crciisc " for that Com- 

 mittee or the Academy, their mode of proceeding being in itself 

 altogether unreasonable and irrationil, I can point out what I conceive 

 would tend to abate, if not entirely correct, the inconveniences novf 

 complained of. 



It is almost hopeless to suppose that the Royal Academy will reform 

 any part of its system out of deference to public opinion. Your own 

 Journal and many others have repeatedly animadverted on the very 

 preposterous manner in which drawings are put up in the Architectural 

 Room, many quite insignificant or uninteresting in subject obtaining 

 comparatively good places, while others, far more worth looking at, 

 are thrust where they can scarcely be seen at all; which is surely 

 absurd enough, for if the space allowed to that department of the ex- 

 hibition is su inadequate at the best, all the greater necessity is there 

 that it should be turned to the best account— that the drawings ad- 

 mitted should be chosen with careful regard to their intrinsic merit 

 and interest, and that since they must needs be comparatively limited 

 as to number, they should also be select, and also still fewer than at 

 present, no more being admitted than what can be properly hung up— 

 that is, than can be properly seen and examined after they have been 

 hung up. Frequent, however, as have been the complaints and re- 

 monstrances in regard to the utter want of good management with 

 respect to architectural drawings, the Academy does not pay the 

 slightest attention to them, doubtless because they are not brought 

 before it in such formal manner as would render it impossible for 

 some notice not to be taken of them. What I would, therefore, sug- 

 gest is, that the Institute of British Architects should take up the 

 matter in behalf of the profession, and formally communicate on the 

 subject with the Royal Academy, urging the necessity for some reform 

 and improvement in its exhibitions of architecture, and devising mea- 

 sures whereby such reform might be secured, as far as circumstances 

 will at all permit. Let the Institute do this, the Academy would thea 

 be compelled to return some kind of reply; and however unsatisfac- 

 tory the result might prove, at any rate the Institute itself would have 

 shown a disposition to stand up for the interests of architecture and 

 its professors, whereas the Academy's own professor of architecture 

 does not seem disposed to interfere at all, but to leave the painters 

 and the Hanging Committee to have it all their own way. I shall, no 

 doubt, be told that what I have suggested is pretty much like the 

 notable receipt for catching birds by putting salt upon their tails. I 

 have proposed that the Institute should poke up the Academy ; very 

 good— but then who is first of all to poke up the Institute itself to do 

 any thing of the kind. It surely cannot be required to be told that 

 there is occasion for something being done in order to put the annual 

 exhibitions of architecture upon a much better, and I may add, more 

 respectable footing than they now are ; and if the Institute has hitherto 

 not thought fit to interfere in anv way, though for such laudable pur- 

 pose, is it to be imagined that it will do so now at the suggestion of 

 any one else? Hardy! no matter; it must at least do one thing, dis- 

 posed or not, for its silence will be equivalent to a tolerably plain 

 avowal that it is determined to give itself no trouble, to listen to 

 nothinc proposed by others, more especially if what is so proposed 

 does not immediatelv aftect itself; therefore it must, at any rate, let 

 it be seen with how much or how little public spirit and generosity it 

 is actuated, and how far anxious to exert what influence it may possess 

 for the benefit of the public and the profession. 



I remain, &c. 



Corrector. 



THE PROPOSED NEW CHURCH, KENTISH TOWN. 



Sir- As Mr. Bartholomew expressed himself in his "Specifications" 

 in no very measured terms relative to his brother architects, stigma- 

 tisino- the whole profession en masse, not only for their incompetence, 

 but for various malpractices amounting to fraud, or what he terms 

 Faunlkroi/ism, he has no right to look for much indulgence; nor can 

 he reasonably be surprised if he now finds his own pretensions rather 

 sharply scrutinized. Possibly he may be the only immaculate member 

 in a profession in which- if we are to take his word for it— it would 



