1844.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



45D 



■which he contrived, " The engine consists of a Iriple crank with three 

 pumps, which hoth suck out and force in air hy means of three regulators, 

 and are alternately applied to drive air into, or draw it out from, any place 

 assigned, through square wooden trunks which, being made of slit deal, and 

 ten inches wide inside, are easily portable, and joined to one another without 

 trouble." 4 Dr. D. illustrates his description with notices of several experi- 

 ments. At every stroke, eleven cubic feet of air was driven in, or as many 

 sucked out ; if the axis of the cranks turn sixty times in a minute, one man 

 in that time might change a whole cubic space of eight feet ; and by his esti- 

 mate, a man breaths a gallon, about 287 cubic inches, of air per minute, and 

 a candle, six in the pound, will burn nearly as long in the same quantity. 

 This agrees with modern calculations, at the lowest estimate— 300 cubic 

 inches are contaminated by a man per minute, although Trcdgold and others 

 take the quantity at 800 cubic inches, and a single candle alone at 300 cubic 

 inches. These facts go far to prove the necessity of ventilation, and in expe- 

 riments made on board ships' lower decks (Philosophical Transactions, Vol. 

 47), it is stated that a candle burned 67 grains in thirty minutes where there 

 had been no ventilation for twenty-four hours; after six hours' ventilation, 

 it burned 94J grains in the same time. Combustion could barely be main- 

 tained in the former atmosphere. 



If the utility and convenience of Dr. Desagulier's hand- pumps realized 

 the description given of them, they might still be usefully employed in the 

 ventilation of the lower parts of ships. Many other mechanical contri- 

 vances might be noticed. For instance, the double air force-pump, worked 

 by two or four men, on the principle now in use for diving-bells, which is 

 worked by a lever, upon a standard, on the plan of Dr. Hales' ventilator. 

 Triewald's ventilator (page 383} was probably on this principle. It may also 

 be noticed here that the success which attends forcing down air, into mines, 

 by means of a fall of water, points out how the foul air. which accumulates 

 in the well of a ship, might in a great measure be discharged by letting 

 down to and pumping out fresh water from the well. As the use, however, 

 of mechanical ventilators has been generally, and still may be, even when 

 they are restored to, of temporary duration in sailing vessels, no doubt, 

 chiefly from the want of a motive power, my object in directing attention to 

 a thorough system of spontaneous ventilation has been to show that in my 

 opinion it is most likely, if properly achieved, to be permanently useful. 5 



In steam-ships, however, there can exist no obstacle to the expelling of 

 noxious air mechanically, or the application of a perfect system of mechan- 

 ical or artificial ventilation, nor can there be any reason why they should 

 not be properly ventilated. Yet I question much if anywhere an efficient 

 system has been introduced. I have, indeed, observed of late years an at- 

 tempt to introduce ventilation into the cabins of a few steamers by provi- 

 ding small iron pipes from the ceilings, passing upwards through the deck ; 

 but, unaccompanied as these usually are, with fresh air inlets from above 

 they cannot prove efficient, and only tend, perhaps, to create annoyance ! 

 however the introduction of these acknowledges the necessity for ventilation 

 being provided. 



In the common arrangement of steam-ships conveying passengers, the 

 sleeping births enter from the saloon or main cabin ; hence it may be said 

 that eating, drinking, and sleeping go on in the same apartment. The at- 

 mosphere from such causes soon becomes noxious, which is generally farther 

 increased by what Mr. Dickens, in his American Notes, so strongly con- 

 demns, the red-hot sulphurous stove, the inconvenience of which is increased 

 by passengers crowding round it. No wonder the air in such cabins and 

 saloons is sickening and unpleasant for respiration. During the day, if the 

 weather be fine and hatches open, matters may go on pretty well ; but in bad 

 weather, or during the night, the case is very different. If proper air con- 

 duits or pipes were provided to bring down an ample supply of fresh air 

 from above, distributed at the floors or decks of every cabin and sleeping 

 berth; and from the ceilings of the respective cabins, or vacant spaces be- 

 tween the beams, branch-pipes conveyed the vitiated air to one large trunk, 

 which might be made with proper precaution to communicate with the chim- 

 ney, the engine-boilers, or pass through a steam chest, or encircle the steam- 

 pipe — a constant renewal of the entire air between decks would go on. The 

 current might be checked and regulated by valves, working in a very simple 

 manner, before entering the chimney. In winter, the comfort of the passen- 

 gers might be materially increased were the air warmed before being dis- 

 charged into the cabins — cold oliensive currents would thus be avoided. It 

 is singular that the same idea had occurred to Buchanan, when he wrote, in 

 1810, on heating by steam. "It is worthy of the consideration.'' he says, 

 " of those acquainted with nautical affairs, how far it is applicable to ships, 

 particularly to men-of-war.'' There is generally in steamers very little spare 

 steam; but a very small portion would be requisite to warm the cabins ; or 

 hot water could even be more eflectively employed. In this case, the ex- 



4 The machine was cheaply made— the pumps of copper, and crank of 

 iron. 



5 See " On conducting air by forced ventilation," &c, by the Marquis of 

 Chabannes, London, 1S18, and remarks on ditto, by J. Arnot. 



ternal air, before entering the cabins, might pass through boxes or cases 

 filled with iron or copper pipes heated with hot water or spare steam from 

 the boiler ; or the air itself might pass through the interstices of iron cases 

 similarly heated, and then enter into the cabins through numerous small 

 apertures. Thus warmth and the supply of fresh air could in winter be com- 

 bined. 



I have alluded to the wind-fan having been made use of to supply fresh 

 air or cool the furnace-room, the power being taken from the paddle-shalt. 

 The fan admits of easy extension to the general ventilation of the steamer. 



In some recent instances, ventilators, on the principle of the Archimedian 

 screw, have been tried for this purpose. Ventilators or revolving fans, on 

 this plan which I have seen, are stated to have long been in use in factories. 

 In an extensive flax-mill in Yorkshire, a very powerful fan on the principle 

 of the screw propeller, driven by steam power, has been most successfully 

 adopted, and the plan there in use for imparling moisture to thea'r, is highly 

 deserving of general application, and ought never to be overlooked in ven- 

 tilating arrangements. 



The importance of keeping the furnace- room cool is of great consequence, 

 especially in warm climates, as the heat is injurious to the health— the cold 

 air rushing to the furnace, falis like lead on the heads of the stokers. To 

 remedy the over-heating, though it cannot prevent the draught, a plan, pro- 

 posed by Mr. Holdsworih of [Dartmouth, has recently been tried in the 

 Victoria and Albert, Royal Steam Packet, of having the bulkheads of two 

 plates of sheet-iron, and a stream of cold water kept constantly flowing 

 between. 



Another plan of ventilating, suitable for steam-ships, which the small 

 space it occupies recommends, is the very ingenious method adopted by Mr. 

 Oldham at the Bank of England, of forcing in fresh air, by an air-eon- 

 densing pump, through the interstices of iron cases heated by steam, the 

 power being taken from the steam-engine, as described in the Civil Engineer's 

 Journal, March 1839. This plan gives both fresh air and a modification of 

 its temperature. 



Mr. Taylor's plan, described in the Transactions of the Society of Arts, 

 London, 1810, of pumping out impure air from mines by an air-exhausting 

 cylinder, likewise admits of application to steam-vessels. Mr. Taylor's 

 engine discharged more than 200 gallons of air per minute. ' The idea of a 

 motive power to work ventilators is of very old standing. A plan is given 

 in the Phil. Trans. 1758, of using the fire-engines at mines for this pur- 

 pose. s Various other suggestions might be made to apply ventilation to 

 steam-ships— even the suction from the motion of the paddle-wheels might 

 be made subservient to this purpose; but it is superfluous to say more on 

 what admits of so many ways of attainment. 



It is unquestionable, that the same share of attention has not been paid 

 to the advancement of ventilation, as to other branches of the arts and 

 sciences. A wide field is therefore open for improvements. But to be suc- 

 cessful, these things must not be left to chance ; they must form part of the 

 construction of ships and steamers, and the naval architect and ventilator 

 as has been well observed by Dr. Reid, " must work together." 



While undue currents of cold air must be avoided — which are often 

 troublesome, and must be injurious— ventilation, to be perfect, should be so 

 arranged as to admit of being increased or diminished, according to the 

 number of inmates. In our climate, in steamers, whether in coasting or long 

 voyages, it would be of importance to have the power of raising the tempe- 

 rature of fresh air before admission to cabins; merely giving it, however, 

 that slight degree of warmth that will not be injurious to its hygrometric 

 condition. This would insure a larger volume of air being admitted. The 

 plan is so easily attainable, that it might lead to the dispensing, iu a great 

 measure, with close arid stoves, so detrimental to the health in confined 

 situations. It is remarked, that even C'elsus, amongst the ancients, recom- 

 mended large rooms for the sick, or a fire in the chimney to draw off bad 

 air. Where fire-heat is made use of in cabins, it ought, if possible, to be in 

 open fire grates. An ample exposition of the injurious etiects of close 

 stoves will be found in the Architectural Magazine, May 1838, p, 231, by 

 Julius Jeffreys, Esq. 



In September 1842, a patent was granted to Robert Hazard, of Clifton, 

 near Bristol, for improvements in ventilating carriages and cabins of steam- 

 boats. He proposed to remove the vitiated air within a carriage by means of 

 a fanner fixed at a convenient place, and set in motion by the revolution of 

 the wheel, or by other motive-power. He does not specily bow he intended 

 to apply his fans to cabins, but as regards the application to the latter, there 

 is little scope for novelty. — Rep. of Arts, May 1843. 



7 Mr. Taylor's plan consisted in attaching a pump of simple construction 

 to a small fall of water of about 12 feet. Steam-power could be substituted 

 for water. 



8 It was first proposed by Erasmus King, to have ventilators worked by 

 the fire-engines ol mines; and Mr. Fitzgerald, in 1758 (see Phil. Trans ), 

 suggested an improved method of doing so. I have alluded to the similarity 

 of mine-ventilation with that of ships; thus, by having a series of flexible 

 pipes connected with a wind-engine, or an air-pump attached to a steam- 

 engine, immense supplies of air might be driven in, or drawn out, where 

 required. 



