1839.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



97 



This apparatus In the Bank of England, independently of heating 

 and ventilating several large apartments, is put to the severest test 

 namely, that of evaporating the moisture from a series of 400 large 

 mill-boards, with a surface of 1000 feet, and which moisture they have 

 absorhed from the fresh-printed bank notes which are daily dried by 

 this process. 



Witli respect to the quantity of heat which this small apparatus is 

 capable of imparting to the air, this is accurately tested by the quantity 

 of water which is condensed, and which amounts hourly to twelve 

 gallons. Now, as Professor Brande observed, when we consider what 

 an enormous body of heat is contained in the steam generated from 

 twelve gallons of w ater, we are enabled to appreciate the iiourly eftective 

 heating powers of this apparatus. 



As to the volumes of warm air that may be required, tliat will of 

 course depend on the cubical contents of (he buildings to be heated. 

 This, however, may be stated, that there is scarcely any limit, eitlier to 

 the quantity of heat which may be thus given out, or the quatitity of 

 fresh air, so heated, that may be propelled by such a system. Of the 

 mechanical means by which this artificial current of air is created, little 

 need be said, these are within tlic reach of all. 



Of the efficacy of an artifical current produced by means of a fan or 

 cylinder, Dr. Urc observes, that " it has been ascertained that a power 

 equivalent to one horse, in a steam engine, will drive at the rate of 80 

 feet per second a fan, the effective surfaces of whose vanes, and whose 

 inhaling conduits have each an area of 18 inches sfpiare, equal to that of 

 a large steam boiler chimney. The velocity of air in the chimney, 

 produced by a consumption of fuel equivalent to the power of twenty 

 horses, was no more than :i.j feet per second ; while that of the fan, as 

 impelled by the power of one horse, was (iO feet per second. Hence it 

 appears, that the economy of ventilation by the fan, is to that by the 

 chimney draught, as OS is to vij or, 38 to 1 . It is obvious, therefore, 

 that with one bushel of coals consumed in working a steam-impelled 

 excentric fan, we can obtain <is great a degree of ventilation, or we can 

 displace as great a volume of air, as we could with 38 bushels of coals 

 consumed in creating a chiunicy draft. Economy, cleanliness, and 

 compactness of construction, are nut, however, the sole advantages 

 which the mechanical sjstem of ventilation possesses over the physical. 

 It is infallible, even under such vicissitudes of wind and weather, as 

 would essentially obstruct any chimney drauglit ventilation ; because it 

 discharges the air vsith a momentum quite eddy proof; and it may be 

 increased, diminished or stopped altogether, in tlie twinkling of an eye, 

 by the mere sliifting of a band from one pulley to another. No state of 

 atmosphere without, no humidity of air within, can resist its power. 

 It will impel the air of a crowded room, loaded with the vesicular 

 vapours of perspiration, with equal certainty as the driest and most 

 expansive." 



After so clear and practical an exposition of the advantages of a 

 current, mechanically created, nothing further need be said of natural 

 currents arising from mere increase of temperature, excepting that by 

 the adoption of the pump instead of the fan, a very considerable power 

 is saved, and the operation performed much more effectively. 



Another peculiarity of Mr. Oldham's apparatus here merits atten- 

 tion. The large volume of air heated and passed off to the required 

 apartnienls is, previously to its being received into the heating chest, 

 filtered and putilied, by being deprived of all that noxious floating 

 matter with which the atmosphere, particularly that of London, is at 

 all times charged, and which, if heated and sent into the apartments 

 with the air, would but increase that noxious character and render it 

 still mote injurious to the respiration of hiuiian beings. Not only 

 indeed arc these offensive impurities which are floating in the atmo- 

 sphere effectually separated, but a power is given of charging it with 

 aromatic or antiseptic matter, thus rendering it not only the medium 

 of warmth and ventilation, but of purifying and healthful influences. 

 The peculiarities of Mr. Oldham's arrangements then, are, first, the 

 adoption of mechanical means for the creation of/i current of hot or 

 cold air, and which may be augmented to any required extent or 

 volume, instead of that comparatively feeble current wliich results from 

 the difference of temperature alone ; secondly, the causing this artificial 

 current of air to be heated by a peculiar arrangement which separates 

 its volume spontaneously into their horizontal films, thus making them 

 pass in contact with a corresponding immber of surfaces heated by 

 steam, imparting a large volume of heat to a large volume of air in a 

 small space and with great rapidity — and when so heated, of again 

 unitina these films — to be passed up in a body in whatever direction or 

 to whatever distance may be required ; thirdlj', the filtering the air 

 before it is received into the heating apparatus, thus efiectually ex- 

 cluding that offensive dust and black matter with which the atmosphere 

 is charged. I am. Sir, &c. C. W. WILLIAMS. 



[We will, in our next Journal, if possible, give the drawings of Mr. 

 Oldiiam's apparatus.— Ediiok.] 



MACHINE FOR CLEANING AND REPAIRING FRONTS 

 OF HOUSES, &c., OR A FIRE ESCAPE. 



Sir, — As the many melancholy instances of loss of life by fire have 

 occasioned a very general interest in the invention of Fire Escapes, I 

 beg the favour of your notice of one which I think has all the desiderata 

 mentioned by Captain Manby, in his address to the Society (or the Pro- 

 tection of Life from Fire, namely, simplicity, portability, and efficiency. 

 I may add to these, economy in construction as being not a whit less 

 important, seeing that the cheaper such machines can be made the 

 greater will be the chance of their being kept in every part of the me- 

 tropolis ; the expense of mine will not exceed seven poinids ; and in 

 quantities, I have no doubt they may be made for a third less. 



As I do not pretend to be more 

 than an amateur in mechanics, I 

 fear I shall very ill explain my- 

 self. By reference to the an- 

 nexed sketch it will be seen that 

 my invention consists of a car 

 traversing u\> and down the iimer 

 or under side of a ladder, which 

 it uses as a sort of inclined rail- 

 way, and is suspended to the top 

 ro\nid of the ladder by means of 

 a chain passing over a pulley of 

 a snatch block. The car maybe 

 adj usted to any sized ladder, which 

 is admitted within the double 

 framework of the machine be- 

 tween four rollers (two at the 

 top and two at the bottom), each 

 of which have occasionally a bear- 

 ing on the ladder, but generally 

 only the lowest inside and the 

 upper outside rollers. The car 

 weighs, including a single fall 

 rope and block, about 90lbs,and 

 I propose that every fire engine 

 should carry one, which may be 

 attached ver)' ornamentally at 

 the opposite end to the driving 

 ■^box. 



By means of this car a fireman 

 could be raised to the upper 

 windows of a house without dif- 

 ficulty by three persons, and thus 

 atlbrd personal help to those in danger, who, nine times in ten, have not 

 presence of mind to avail themselves of the aid thrown up from below. 

 As the car descends with the inclination of the ladder, it of course 

 recedes from the front of the house ; it is, however, enabled to put forth 

 in case of need an additional projection or stage of four feel, as shown 

 in the sketch, whicli I believe would be the utmost required. Such a 

 machine will also be found very useful for builders, plasterers, painters, 

 and others, for the purpose of repairing, cleaning, colouring, or painting 

 fronts of buildings. If generally adopted for such purposes, hardly a street 

 would be without one, which would form an additional certainty of the 

 fire-escape being ready in case of need. 



I need not be reminded that my invention is nothing without a ladder ; 

 but as fires very rarely happen without their being speedily procured in 

 the neighbourhood, there cannot be any difficulty on that point. 



Hoping to obtain, through jour widely circulated publication, some 

 practical opinion of the machine, I intrude this communication. 



And remain, Sir, yours, &c.. 

 Nine Elms, December 31, 1838. A, F. 



THE NATIONAL GALLERY. 



Sir,— I had been for some time coveting a little leisure to submit 

 a few opinions to you on this ill-fated building, when the " Supple- 

 ment to the Public Buildhigs of London," by Mr. Leeds, informed me 

 that my intentions were anticipated by one much more competent to 

 speak upon the subject. The points to which 1 more immediately 

 intended to advert, were for the most part those ou which Mr. Leeds 

 has so foicibly couunonted, viz., the absurdity of accusing the archi- 

 tect of having diminislied the capacity of the building by the very 

 measures which, on the contrary, increased it (see pages (i'J, 6ii) ; tlie 

 inconsiderate outcry concerning its being "too low" see pages 67, 

 68) ; and the injustice of " censuring in the lump, without caring to 

 hint at particular beauties in what upon the whole may be defective." 



It is not for m« to presume that wnything- emanating from 60 hum- 



