356 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[NOVEMBEB, 



Has our occupation of Indi;i produced equal advantages to the 

 native trilies? Have we done so much to assist their advance 

 in civilisation? If not, have we not rather abused our strength 

 than fultilied the duty our superior intellectual position imposes 

 onus; and shall we not suffer the ])enalty sooner or later? A 

 foreiifu nation never can retain ])Ossession of another cmintry, 

 unless it secure to its su!>jects a greater amount of happiness and 

 prosperity th.m it C(Mild procure itself. Doubtlessly, the native 

 kinjTsof India did less for their subjects than the Company has 

 done; but the examjjle of the French government would lead us 

 to ipiestion whetlier we have fulfilled our whole duty. There are 

 in India far less artificial means of communication tlian there are 

 in Al:;eria. Yet what are the relative populations, surfaces and 

 es|)ecially, what are the revenues obtained in the respective cases? 

 For it is to be observed, that Algeria has cost France at least four 

 millions sterliuj; per annum for the last 20 years, whilst India 

 yields a large sum to be divided amongst the share or bondholders 

 every year. 



Geo. R. Burnei.l. 



SuuthiwipUm, Oct. ^3rd, 1850. 



VENTILATING APPARATUS. 



In No. 152 of the Journal (p. 1+5), we pointed out the efficient 

 internal arrangements of the York County Lunatic -Vsyluni, of 

 which we gave the plans and elevation. Among these arrange- 

 ments, which we could not then particularly describe, is the venti- 

 lating apparatus, which was exhibited to several architects and 

 men of science at the warehouse of Messrs. Baily, ironmongers, 

 High Holborn. This apparatus is constructed under the direc- 

 tions of Dr. Arnot, and was exp'ained by him to Lord W'riothes- 

 ley. Sir Thomas Deane, Dr. Ure, Professor Donaldson, Mr. Fowler, 

 Mr. Godwin, Mr. Laxton, and some other gentlemen. Those who 

 know the enlightened, energetic, and disinterested efforts of Dr. 

 Arnot for the extension of mechanical a])pliances in aid of 

 hygienic science, will not fail to receive with pleasure this new 

 application of his ingenuity. The water-bed, mucli as it may he 

 justly esteemed by medical men, is no less an admirable exemplifi- 

 cation of mechanical skill in the adaptation of simple means. 

 The apparatus which we are now about to describe, is likewise 

 very simple, and at the same time promises to be very effective. 



The apparatus is shown in the annexed engravings, of which 

 fig. 1 is a plan and fig. 2 a section, taken through the centre from 

 A to B. It consists of a fixed cylinder, placed in the centre of a 

 room, and which cylinder is about 5 ft. 6 in. diameter and 5 ft. high; 

 with a chamber above and below, each furnished with inlet-valves 

 to receive the air from the fresh-air shaft, and outlet-valves to 

 deliver the air into the adjacent chamber, and thence distributed 

 through the building. The cylinder is made of galvanised iron, 

 is open at both ends, and has an outer case at about ,3 inches 

 distance, and the whole depth of the cylinder filled with water, 

 which forms an annular hydraulic joint. Within this cylinder is 

 another cylinder, 5 ft. 9 in. iliaineter, inclosed on the to|), similar 

 to the rising bell of a gas-liolder; the rim of this cylinder works 

 up and down in the water contained in the annular rim just 

 des(-ribed. By this arrangement the communication with the 

 upper and lower compartments is cut off. 



'I"he working cylinder is suspended to the end of a moveable 

 beam about 10 feet long, and balanced by a weight or bid) sus- 

 pended to ttie other end, ecpial in weight to the moveable bell, 

 minus a sufficient weight to cause the l)ell to descend and expel 

 the air in the lower compartment. Now, for the purpose of setting 

 the beam in motion, it is necessary to have some moveable power 

 to overcome the friction of the moveable parts and the air. For 

 this purpose Dr. Arnot has adopted a single action water-engine, 

 havinjf a cylinder 2 inches diameter and 12 inches stroke; to be 

 supplied by water from a reservoir placed on the top of the build- 

 ing, 60 feet above the engine. A column of water of this altitude 

 acts with a pressure of about 30 lb. on every moveable square inch 

 of the piston; and if the piston be 2 inches diameter, it will be 

 equal in round numbers to 3 si|uare inches, consequently the force 

 of the water acting on the ])iston will be 3 X 30 = 90 lb.; ami 

 this is the power with wliicli the Doctor proposes to wiu-k the ap- 

 paratus, and as the engine is single-acting, the cylinder will 

 require about a pint of water for every stroke. Thus, if the 

 engine works S strokes |)er minute, it will require 8 pints of 

 water, or 1 gallon per minute, to keep the beam moving. 



This engine is placed so that the connecting-rod is connected 

 with the moveable beam at 1 foot from the fulcrum; and if the 

 beam have a radius of 5 feet, and the working cylinder be sus- 

 pended at the end of the beam, the bell will be elevated 5 feet at 

 every stroke of the engine. \Vhen the piston has performed one 

 upward .stroke by the ])ressure of the water, the water is cut off 

 by a slide-valve, and that which is within the cylinder is discharged 

 into an open pipe; consequently, the extra weight of the moveable 

 parts will cause the piston to descend, and at the same time 

 the working cylinder will also descend. Now, if we suppose 

 that at the commencement of the working of the apparatus the 

 working cylinder is close down on to the fixed cylinder, the upper 

 compartment will be filled with air, and as it rises it will displace 

 a quantity of air equal in capacity to the cubic contents of the 

 working cylinder, and force it out of the valves ^hat open out- 

 wards; and at the same time that the cylinder is rising, the space 

 below is increasing equal in ca])acity to the cylinder, and a quan- 

 tity of air rushes in through the valves opening inwards, and fills 

 up the space; and when the bell begins to descend, the lower inlet- 

 valves close and the lower outlet-valves open, and the air that is 

 below is forced out through the outlet-valves of the lower com- 

 partment, and at the same time the air is being admitted into the 

 upper compartment, as before described. By this means the action 

 is double, and a constant stream of air is being taken in through 

 either of the inlet-valves, and forced out through the upper or 

 lower outlet- valves into the adjacent chamber, and thence through 

 trunks and cases to all parts of the building. 



Now, it has been shown, that for every stroke of the engine the 

 working cylinder displaces a quantity of air equal to its capacity 

 in both the bottom and upper compartments; and as the capacity 

 of the working cylinder is equal to 125 cubic feet, it displaces in 

 both compartments 250 cubic feet for every upward and downward 

 stroke of the engine, at an expense of one pint of water, descend- 

 ing from an altitude of 60 feet; and if the engine works 8 strokes 

 per minute, it will displace 2000 cubic feet of air, at an expense of 

 8 ])ints, or one gallon of water, which is equal to 2,880,000 cubic 

 feet of air, displaced by the aid of 1+40 gallons of water for 24 

 hours. These are the proportions proposed by Dr. Arnot for 

 ventilating York Hospital. 



For the purpose of feeding the apparatus, pure air is brought 

 down a shaft, the top of which is considerably above the top of the 

 building, and which communicates at the bottom with the chambers 

 before described; and if it be desired that the air be warmed, it is 

 effected by allowing the air, as it is expelled from the chambers, 

 on its passage to the trunks, to pass between a series of hollow 

 copper vessels filled with hot water. 



The adaptation of the water-engine, which Dr. Arnot proposes 

 to adopt, is particularly desirable, as it can be worked at compara- 

 tively little expense, and the water, after it has done its work in 

 the engine, may be used for domestic purposes. It will also be 

 seen that by this apparatus the whole of the air forced in for ven- 

 tilation can be accurately measured if a counter be attached to 

 the engine to show the number of strokes the engine has performed 

 during the day. 



Reference to Engravini/s. 

 Similar letters refer to similar paits in each figure. 



A, is a fixed cylinder, open at both ends with outer case a, filled with water, 

 forming an annular byilranlic joint. 



B, working cylinder inclosed on the top and open at the battom ; the rim 

 works up atid down in the bjdraulic joint a, 



C, C, upper and lower chamliers. witli inlet valves iv, opening inwards to 

 take in the air from the exttrnal air-shaft E; and outlet valves ov, open- 

 ing outwards to convey the air to the shaft D, and thence to the building 

 through the trunk T. 



F, furnace-room, in which is placed the boiler with four square fire-boxes 

 f,f,f.f, to heat the water for supplving the copper cells g, when it is 

 requiri-d to warm the air as it is being forced into the huddnig; there are 

 several of these copper heating cells placed side by side, with narrow 

 spaces between for the air to pass through, 



H, a water-engine, acted on by a column of water on one side of the piston, 

 which is lirou|;ht by a pipe h, from a cistern placed on the roof 60 feet 

 a''Ove ; ^'. is an air-vessel to prevent concussion by cutting off the water 

 suddenly; k, gear for opening and shutting the eduction and induction 

 valves; /, piston and connecting-rod. 



K, biilance-heam ; at one end is fixed a chain to suspend the working 

 cyluidcr, and at the other end is another chain to suspend a balance- 

 weight m. 



