lft.39.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



1 35 



ON 



THE MEANS GENERALLY EMPLOYED FOR 

 REMOVING RUINOUS BUILDINGS. 

 We possess many books which contain every information regarding 

 the construction of buildings — from tlie laying of their foundation-stone 

 up to the completion of their minor details. We are, however, not so 

 well informed as to the method of taking these buildings down when 

 they become ruinous, although it is often a more ditficult operation 

 than their erection; and the advantageof being possessed of information 

 on this apparently otit-of-the-way subject is really greater than a 

 general observer is inclined to believe, more especially when it is con- 

 sidered that many of the houses lately erected have sprung up in an 

 incredibly short space of time, and have been constiucted of materials 

 not calculated to withstand the vicissitudes of our tempestuous winters, 

 nor to resist the effects of any sudden accident. It seems to us that 

 the autliorities of all large towns sliould be prepared with means for 

 removing the walls of such buildings when they happen to be suddenly 

 deprived of their usual support by fire, or the failure of any of their 

 parts : and yet, so far as we are aware, no attention whatever has been 

 devoted to this subject — and it is on these grounds that we venture to 

 oft'er a few remarks on the methods generally employed on such 

 occasions. 



In situations where the erection of scaffolding is inexpedient, the 

 methods commonly resorted to are those of pulling down the walls 

 en masse by means of chains, and of blasting with gunpowder. 



We have seen the first of these methods often put in practice, but 

 never with such signal want of success as about two or three years ago, 

 where a gable wall of rubble masonry, about 50 feet high, 150 feet 

 broad, and perhaps 2 feet tliickness, liad to be removed. Although 

 forty or fifty persons were engaged pulling and tugging at the end of the 

 chain, prefacing each effort with a nautical shout, which they seemed to 

 expect would mateiially contribute to the efficiency of their exertions, 

 they seldom pulled down considerable masses, and never succeeded in 

 disturbing the equilibrium of the whole mass. There was, indeed, one 

 cause that operated strongly against the success of the experiment, 

 whicli was, tlie want of heepiiit! time ivith the oscillation of the mass. 

 Wlienever the wall was thrown in the least degree from the perpendi- 

 cular, the chain should, of course, have been pulled in concert with the 

 vibrations, whicli, being always increased, would at last have thrown 

 the centre of gravity of the greater part without the base, and the 

 whole fabric would then have fallen to the ground. But instead of 

 being pulled by a band of trained men, the rope was subject to the con- 

 troul of the whole mob, who, by never pulling in concert, rendered 

 their exertions worse than useless. After much time had been lost in 

 these fruitless attempts, l/lasting icas tried icith perfect success. To 

 those who had never witnessed the effects of gunpowder employed in 

 such a way the plan appeared more hazardous than experience after- 

 wards proved it to be, fur not a stone was' thrown ten, or, at most, fif- 

 teen feet, from the bottom of the wall, and in no instance where it lias 

 been tried have we ever seen stones scattered to a greater distance. 



From this account it will be seen that blasting is by far the most 

 efficient and safe agent that can be employed in levelling ruins. Had 

 the wall been thrown down by a system of pulling:, the stones, from 

 the impetus acquired in falling from a vertical to a horizontal position, 

 would have been scattered and thrown to a great distance, at the 

 manifest risk of those who were below, andj^of the neighbouring 

 houses. 



In blasting, the lower courses of the masonry are shattered, and a 

 shock, sufficient to disintegrate, and, sometimes, even bodily to lilt 

 np the superincumbent mass, is propagated from top to bottom. The 

 dangers to be apprehended are, first, the possibility of one or more of 

 the stones being thrown to some distance ; and, second, the possibility 

 of only some part of the lower courses being blown out, while the 

 remainder is left ; so that the wall is apt to turn on that part as a 

 centre; in which case it may appear proliable it would fall in the 

 direction in which there was no support. 



First. — The danger of one or more uf the stones being thrown to a 

 distance seems a probable one ; but, in so far as our observation has 

 gone, this has never occni red. The action in blasting a solid mass of 

 rock, is different, wc think, from blowing up an artificial concrete-like 

 masonry ; for, in the one case, the gases formed by tlie explosion have 

 no room to expand themselves, unless by rending the compact rock, 

 whose particles are cemen'ed in the closest union ; while, in the other 

 case, there are numerous fissures, affording much greater room for 

 expansion. 



Second. — The second danger is little to he dreaded, as the whole of 

 the lower courses are alivays either completely removed, or else so 

 shattered as to yield to the slightest pressure But in every case 

 ■which has come under our observation, the wall itself hiis been at least 

 perfectly disunited from top to bottom, by the shock resulling from 

 the blast. 



Although we can easily conceive thi' possibilily of either or botli of 

 these accidents occurring, slill we think ourselves perfectly justified 

 in deiidedly reromuiending blasting in preference to the other methods 

 we have alluded to. We do so, not because we have arrived at that 

 conclusion by any reflection on the subject, nor yet because we have 

 heard it praised by those whose opinion, as practical men, is to be valued, 

 but because we have ourselves been witnesses of its effects. 



It must, however be observed, tliat without judicious superintend- 

 ence, this powerful instrument (like all others) may, from incautious 

 api lication, prove in the highest degree destructive in its effects. 

 Prudence in the selection of situations for the bore, and caution in 

 charging and firing are indispensable requisites for safety; and even 

 where attention is paid to all these essentials many unloresecn circum- 

 stances may, no doubt, occasion what all possible care could not 

 prevent. 



We may state, in conclusion, that although some may consider the 

 removal of ruinous walls as not an oper.ition in which engineers or 

 architects arc ever, or at least often, to be engaged, we think that 

 oueht in no way lo make these remarks the less important ; for any 

 sudden accident niaj render peremptory measures necessary, and upon 

 the success of these measures valuable property, and even human 

 life, may depend. 



PANORAMAS OF ROME AND THE COLISEUM. 

 The two subjects now exhibiting in Leicester-square have claim 

 upon our notice, as being of considerable architectural interest ; tlie 

 one as a general representation of Rome, sliowing all the buildings 

 visible from the tower of the Campidoglio, on which the spectator is 

 supposed to stand ; the other, of that wonderful fabric, the Coliseum, 

 whose interior, with its arena, is shown as beheld from the top of its 

 walls at its southern extremity, whence the eye also looks down iipon 

 the nciglibouring arch of Constantino, and several other edifices. 

 Although the smaller of the two, and of less variety of interest in its 

 subiect^tliis painting is more striking and captivaling than the other, 

 in regard to scenic eifect and tlie illusion it produces. It conveys a 

 most perfect idea— at. least as perfect as can be obtained from the 

 single spot to which the spectator is fixed— of the structure in its 

 present state, of its prodigious massiveness, and of the ancient 

 Roman brickwork of whicli it is composed. The look of reality is 

 quite astonishing, and the more we contemplate the building, or 

 parts of it, the more docs it increase. Yet it is puzzling to account 

 for the extraordinary relief, there being little of positive shadow, 

 since even the parts'on which the sun does not fall are shown as 

 distinctly as in ordinary daylight, owing to the strong reflection 

 which renders their local colouring visible in all its hues. The other 

 view- is not so remarkable for this deceptive quality, for though ad- 

 mirably executed it has not so vivid an air of reality, being apparently 

 painted in a lower key. Perhaps, too, something may be owing to 

 the .subject itself, aj being less favourable to illusion. Still there are 

 parts of prodigious effect- for instance, the two side buildings or 

 wings of the Campidoglio, immediately beneath the spectator, seen 

 as he looks down upon them from the tower in the centre one. 

 Again, tlie dome of the small church, close by Trajan's column, is of 

 most forcible relief. By specifyiHg these instances, we do not mean 

 to say that the rest of the picture is not so well painted, but the two 

 buildings we have mentioned, being much nearer than most of the 

 others, of course sliow themselves more distinctly. St. Peter's is too 

 remote to be a principal architectural object; but in a view taken 

 from the Castle of St. Angelo, both that and the Vatican would be 

 very prominent objects, and occupy a considerable portion of the 

 scene. In our opinion, such other general view of Rome would be 

 —we will not say worthy of Mr. Burford's jiencil, since of that there 

 can be no douljt- but eminently attractive to the public: nor at all the 

 less so, because preceded by the one he is now exhibiting. 



ISOLATED HARBOURS OF REFUGE. 



In the last number of the Engineer and Architect's Journal, p. 8.5, 

 Mr. Rooke remarks that, as there is no tidal ecour provided for the in- 

 terior of Mr. Tait's isolated harbour, although shingle could be dis- 

 posed of along shore, " might not," he says, " silt eventually choke up 

 such a harbour V" 



Why, the very same remark might, with nearly equal propriety, be 

 applied to a wet dock. Water admitted into a dock or harbour, must 

 be pure indeed not to deposit while there, in a state of couq)arativc 

 rest, a sediment of earthy or other matter in twenty or thirty years 

 time. This of course was to be anticipated. It is obvious, however, 

 that there can be no difficidty in removing such silt by dredging, or 

 otherwise, at no great expense, whenever it siiall be found to be incon- 



