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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Junk, 



ON THE PERFECT VENTILATION OF LAMP BURNERS. 



In consequence of the injury sustained by the books in the library 

 at the Athenaeum Club, amounting almost to the entire destruction of 

 the bindings; and the complaints of the members of the vitiated state 

 of the air in the rooms, causing headache, oppressive breathing, and 

 other unpleasant sensations ; Professor Faraday's attention as a mem- 

 ber of the club, was drawn to the subject of ventilating lamp burners 

 in houses ; and he was induced to suggest the trial of various plans 

 for affecting the removal of the products of combustion, produced by 

 sources of artificial light. All substances used for the purpose of illu- 

 mination, may be represented by oil and coal gas ; although tallow and 

 ■wax are also greatly employed, yet as until they are rendered fluid 

 like oil, they cannot be burnt, they may for all practical purposes be 

 classed with it. Now, oil and gas both contain carbon and hydrogen, 

 and it is by the combination of these elements with the oxygen of the 

 air, that the light is evolved. The carbon produces carbonic acid, 

 which is deleterious in its nature, and oppressive in its action in closed 

 apartments, and the hydrogen produces water. A pound of oil con- 

 tains about 012 of a pound of hydrogen, 0-73 of carbon, and 0- 1 of 

 oxygen ; when burnt it produces 106 of water, and 2*86 of carbonic 

 acid, and the oxygen it takes from the atmosphere is equal to that 

 contained in 13-27 cubic feet of air. A pound of London coal gas 

 contains, on an average, 0-3 of hydrogen, and 0*7 of carbon ; produces 

 ■when burnt, "2-7 of water, and 2-5t> of carbonic acid gas ; consumes 

 4-26 cubic feet of oxygen, equal to the quantity contained in 19*3 cu- 

 bical feet of air. So a pint of oil, when burnt, produces a pint and a 

 quarter of water ; and a pound of gas produces above 2i pounds of 

 water; the increase of weight being due to the absorption of oxygen 

 from the atmosphere, one part of hydrogen taking eight by weight of 

 oxygen, to form water. A London Argand gas lamp, in a closed shop 

 ■window, will produce in four hours, two pints and a half of water, to 

 condense or not, upon the glass or the goods, as it may according to 

 other circumstances happen. Also, a pound of oil produces nearly 

 three pounds of carbonic acid, and a pound of gas, two and a half 

 pounds of carbonic acid. Now carbonic acid is a deadly poison, an 

 atmosphere containing even one-tenth of it, is soon fatal to animal 

 life. The various accidents from lime and brick kilns, from brewers' 

 vats, occasionally from the sinking of wells, as at Cheltenham, and 

 from the choke damp in coal mines, attest the extreme danger con- 

 tingent upon the presence of this substance. A man breathing in an 

 atmosphere containing 7 or 8 parts of carbonic acid, would suffer, not 

 from any deficiency of oxygen, but from the deleterious action of the 

 carbonic acid. M. Leblanc has recently analysed carefully the con- 

 fined air of inhabited places, and concludes, as stated in his Memoin, 

 that the proportion of carbonic acid gas in such places, may be re- 

 garded as measuring with sufficient exactness, the insalubrity of the 

 air ; that in the proportion of one part to a hundred of air, ventilation 

 is indispensable for the prevention of injury to the health ; that the 

 proportion of carbonic acid gas had better not exceed a five hundredth 

 part, though it may rise without inconvenience, to a two-hundredth 

 part. If a lighted taper be applied to the top of a lamp chimney, it 

 will be instantly extinguished, or a glass jar held over it will become 

 immediately filled with air, in which a light cannot burn. Also sul- 

 phurous and sulphuric acid, are contained in the water which results 

 from the combustion of coal gas, and are products injurious to metals 

 and articles of furniture. 



It will now be understood, that the object sought to be attained in 

 the ventilation of lamp burners, is the entire removal of all the noxious 

 products of combustion. And with this view, at Professor Faraday's 

 suggestion, the gas lights of the chandelier in the library at the Athe- 

 naeum, were ventilated by pipes dipping into the lamp glasses, and 

 conjoining at a short distance upwards into one central pipe, which 

 carried away all the burnt air out of the room. In this first practical 

 experiment, many things were learned as to the mode of arranging 

 the pipes ; the disposal, when the pipes were very long, of the water 

 produced, &c; but the objects sought for by the ventilation, were 

 at once and perfectly obtained. This principle may be illustrated by 

 a simple experiment, showing the difference between allowing com- 

 bustion to give its products to the air of a room, and carrying off these 

 products as soon as formed to the exterior, let a short wax candle be 

 placed burning on a plate, a glass jar put over it, and the upper aper- 

 ture of the jar closed by a globular cork, through which passes a piece 

 of glass tube, about half an inch in diameter, and twelve or fourteen 

 inches long ; the tube descending to the top of the candle flame, and 

 being placed just above it. Under these circumstances there will be 

 plenty of air passing into the jar, between it and the plate, and out 

 by the tube, to supply all that is needed for combustion, and keep the 

 glass chamber sweet ; the consequence is, that in this position it will 



go on burning for any length of time, and the jar remain quite clear 

 and bright ; but on moving the cork a little, so that the tube shall no 

 longer be over the flame ; all these results will change, though the 

 air way remains exactly as before. The candle will now give the 

 products of its combustion to the general air of the glass chamber, the 

 glass will immediately become dull, from water deposited upon it, the 

 air itself will become worse and worse ; the light become dim, and 

 in a few minutes will go out. But if arrested from doing so by the 

 tube being again placed over it, signs of recovering will appear, the 

 light will return to its former brightness, and after a short time, even 

 the dew will disappear from the glass; all in consequence of the 

 proper ventilation of the light. These effects, though striking, may 

 easily be understood by any one who will think of the difference of 

 lighting a fire in the middle of a room, instead of under, or in right 

 juxtaposition to a chimney. 



Then came the desire of modifying the system, by removing the 

 ascending flue from its place over the lamp, not from any deficiency 

 in action, but for appearance sake only ; and finding that there was 

 sufficient ascension power in the main part of the metal chimney, to 

 allow of a descending draught over the lamp, the tube, in place of 

 going directly upwards, was made to turn short overtha edge of the 

 glass, to descend to the area or bracket, to pass along it, and then 

 ascend at the central part of the chandelier, or against the wall if ap- 

 plied to a single light. To this succeeded another form, which is 

 exceedingly beautiful, and appears to be the perfection of lamp ven- 

 tilation. It is in fact, a beautiful application of the principle of a 

 descending draught to a lamp burner. The gas-light has its glass 

 chimney as usual, but the glass holder is so constructed as to sustain 

 not merely the chimney, but an outer cylinder of glass, larger and 

 taller than the first i the glass holder has an aperture in it, connected 



Fig. 1. 



Fig. 2. 



Fig. 1. — a, is the burner; b, the gas pipe leading to the burner ; c, the glass 

 holder, with an aperture in it opening into the mouth-piece rf, which is 

 attached to the metal chimney, i ; e, the ordinary glass chimney ; /, an 

 outer cylinder of glass closed at the top by a plate of mica, g, or still 

 better, by two plates of mica, one resting on the top of the glass, and the 

 other one, h, dropping a short way into it j they are connected together by 

 a metal screw and nut. which also keeps them a little apart from each 

 other, thus forming ;i stopper which cannot be shaken off the glass chim- 

 ney, but is easily lifted on and off by the small metal ring or knob at the 

 top ; i, is the metallic tube chimney ; k, a ground globe, which may lie 

 applied to the lamp, and which has no opening except the hole at the bot- 

 tom, where it rests on the glass holder; but any other form, as a lotus 

 glass or a vase, may be substituted at pleasure. 



Fig. 2, is a plan of the glass holder, showing the burner, a. in the centre, per- 

 forated with jets, with openings round it to allow of a free admission of 

 air to the flame, and the aperture rf, which opens into the mouth-piece, 

 connected with the metal chimney, i. 





