316 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[September, 



of tlicse styles at pleasure, and follow it OMt in the spirit in which it 

 was then foUoweii, and in which is the only hope of success. It is 

 like transporting the trees ol the tropics into tliis country, where only 

 the most assiduous attention can keep them alive — nothing can ever 

 make them equal in beauty the natural growth of the trees of our own 

 forests, though in their native climate thev may as much surpass them 

 as llioy now fall short. 



S. L. 



THE ROYAL ACADEMY. 



Sir — I am very glad to perceive that painters as well as architects, 

 are at length beginning to remonstrate against tlie trulv preposterous 

 system of hanging jjictures and drawings at the Royal Academy. Let 

 us hope that what has lately been sai<l on the subject both in your own 

 Journal, and the Art-Union, will now shame the Academy into common 

 sense, and deter them in future from taking in more works than can 

 be properly seen wlien hung up. 



Of course this would contract their catalogue to about one-half its 

 present extent— in which case it might be sold to tlie public at half 

 its present price, — but both the public and artists would be benefitted 

 by the reduction — I do not mean of tlie price of the catalogue, but of 

 the dense throng of pictures and drawings, the majority of which are 

 annually put out of sight, by being ixalltd to disgrace— to their own 

 disgrace and to that both of the Hanging Committee in particular, 

 and of the Academy generally. 



Still it is very doubtful whether the expostulations and remonstrances 

 that have been made will produce any effect, unless repeated from 

 time to time, and dinned in the ears of the Academicians, until they 

 can no longer aflect to be ignorant of them. Did the matter rest en- 

 tirely with the President, the evil complained of would no doubt be 

 remedied at once, but I suspect that like some othergreat personages, 

 he is no more than "the puppet in the chair," and permitted to fill 

 it on the condition of his napping in it, and not interfering with 

 those around him. Though these composing them may be well-in- 

 tentioned and reasonable people, corporate and public bodies are 

 almost invariably shameless, and do not scruple to do in their united 

 capacity, what hardly one among them would dare to sanction, defend, 

 or justify individually and personally. 



In the course of his remarks, the writer in the Art-Union attributes 

 some portion of the present absurd system of hanging pictures in our 

 public exhibitions, to the want of better contrivance and arrangement 

 on the part of architects who build the rooms. Herein he is partly 

 right, but he is assured]^' mistaken if he supposes that, as far as archi- 

 teclural appearances is concerned, any thing would be lost were the 

 rooms to be designed in such a manner as to render it impossible to 

 put any pictures at more than a moderate height above the eye. On 

 the contrary, as much might be gained in point of architectural effect 

 as of positive convenience; since it would not be at all requisite that 

 the proportions of the rooms, as to height, should be altered, or their 

 ceilings an inch lower than at present. All that would be necessary is 

 that no more than a proper altitude should be allowed as the available 

 space for hanging pictures on the walls, (which might vary in the dif- 

 ferent rooms accordingly as they are intended for small or large paint- 

 ings) ; and from that height tlie architectural decoration of the upper 

 part of the walls and ceiling should commence. By this means the 

 general appearance would be very greatly improved ; and instead of 

 the broker's-shop and picture-dealer's-warehouse look, which now so 

 disagreeably characterises all our exhibition rooms, there would be an 

 air of elegance and spaciousness,— of there being room enough and to 

 spare without ston-iiig airaij a number of pictures, piling them up to 

 the very ceiling, when they might just as well be poked into a lumber 

 garret at once. 



In short, let the Academy and other exhibiting Societies break up 

 their Lumber Troop corps, dismiss their host of supernumeraries, and 

 instead of surfeiting their visitors with an annual cram— consisting of 

 a good deal of trash, give us much less as to quantity, and much 

 more as to quality. 



I remain, &c., 



COM.MON Se.n'se. 



PILBROWS CONDENSING CYLINDER STEAM ENGINE. 



This is a contrivance intended, according to a pamphlet written by 

 Mr. Boyman Boyinan, to save the loss of power occasioned by the ini- 

 perfect exhaustion of the cylinder in steam engines of the ordinary 

 construction, and by which Jlr. Pilbrow considers that he will save 

 mon than half \h& fuel of Mr. Watt's Rotative engines. The author 



of the pamphlet in question, however, dispels at the very outset the 

 illusion as to the extent of saving by stating that Mr. \Vatt estimated 

 the mean resistance of the unexhausted steam at 4 Xtt. per square inch, 

 in an engine loaded so as to exert its intended power, the steam being 

 24 ttj. less than the atmosphere. In this case the pressure of the steam 

 is 2i m., from which deducting 4 It), for imperfect exhaustion, and Ij 

 It), for friction fas at page 2S) there remains an effective pressure of 

 G-4() D). The pressure in the condenser at a temperature of 1L»0' is 

 1 tti., therefore the limit of what may be saved by Mr. Pilbrow's arrange- 

 ment is 3 Itj. per square inch, wliich is the entire loss resulting from 

 the exhaustion in the cylinder being less perfect than in the condenser; 

 but if the whole of this were saved, the load of the engine being in- 

 creased, the friction would be so likewise, and the effective pressure 

 would become, say f)-09 lb., and the saving of fuel would be less than 

 29, instead of more than .JO per cent., as anticipated by Mr. Pilbrow. 

 It is evident that the loss in question would not rise in the same pro- 

 portion as the pressure of the steam employed, particularly when it is 

 expanded in the cylinder, which is now pretty generally done to a 

 greater or less extent, and we are persuaded that Mr. Farev must have 

 overrated the resistance of the unexhausted steam, where it is used at 

 3i It), above the atmosphere, when he estimated it at S-'l fli. ; but 

 even with this allowance the consequent loss of duty amounts to no 

 more than 29 per cent. It should be observed that this is the nhole 

 loss due to imperfect exhaustion in the cylinder, which can certainly 

 not be saved by Mr, Pilbrow's arrangement, though he considers that 

 it is. 



Little need be said of the theory of condensation, as it is called, laid 

 down at pages 19 and 2ii, wliich is very little of a theory, and nothing 

 at all to the purpose ; but since it is dragged in, as it were, in con- 

 firmation of the advantages of the Condensing Cylinder Engine, we 

 shall merely show that the inferences intended to be drawn from it are 

 erroneous. 



The theory of condensation is that " steam can only be condensed 

 as fast as it rushes from the cyliniler to the condenser, as far as the 

 injection can enter, and as fast as the water, or cold surface, can absorb 

 all the caloric of the steam." Mr. Boyman concludes that "if the 

 vacuum gauge shows, whilst the steam is being condensed, a less mean 

 vacuum in the condenser than what is due to a temperature of 100," 

 (considered by Mr. Watt as a fair average), "it shows that the steam 

 has flowed quick enough to the condenser, and is there waiting to be 

 condensed," and that " no increase of eduction valve would, therefore, 

 cause a quicker annihilation of the steam, to give a better mean ex- 

 haustion of the cylinder, for it is already large enough to permit its 

 escape as fast as a certain quantity of water can take up its caloric." 

 But what is the just conclusion to be drawn from the above circum- 

 stance ? — Simply that there is not sufficient injection water to reduce 

 the condensemeiit to the required temperature; a knowledge of the 

 actual state of exhaustion in the cylinder would alone show whether 

 the steam flowed fast enough into the condenser. Mr. Boyman harps 

 continually on one string — the impropriety of reducing the condense- 

 ment to a lower temperature than 9G- or 100", and pretends to con- 

 clude therefrom that no better cylinder exhaustion than was obtained 

 by Watt can be achieved with the ordinary air pump, separate from 

 the condenser. 



The long discussion of the comparative performance of Mr. Watt's 

 rotative engines and the present is irrelevant, and we shall therefore 

 discuss it with one or two remarks. 



After extracting Mr. J.S. Russell's proof of the fallacy of the opinion 

 that the better the vacuum the greater is the duty, the author informs 

 his readers that " the above formula is given because it confirms the 

 general principle, that more is lost than gained by a vacuum buyond 

 certain limits. It does not embrace," he says, "the principles of con- 

 densation, but has reference simply to temperature; not," he continues, 

 " that this theory is supported by the practice of Cornish engines, 

 where the greatest duty is performed with the greatest vacuum." 



If, then, this theory is not supported by facts, how can it be said to 

 confirm the general principle ? 



In speakihg of the cilraordinarij Indicator diagrams of the present 

 day, (which seem to puzzle Mr. Boyman exceeaingly, because they 

 show that Mr. Farey's observation, made 14 years ago. Is not applicable 

 to engines of the present day, namely, that "the modern engines are, 

 by their construction, less capable of speedy exhaustion of the cylinder 

 than the original construction"), he mentions that in the diagrams of 

 the British Qua/', where a mean cylinder exhaustion of 12-3 tt>. is 

 shown, the condensement is reduced to the temperature of the exter- 

 nal water, but he does not seem to be aware that tht condensing water 

 lift the condenser at a much higher temperature, \\h\c\\ it must have 

 done, or it could not have condensed the steam. It is however certain 

 that, whatever may have been the state of the vacuum in the upper 

 part of the condenser, where the steam from the cylinder entered i t 



