194 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL 



[Junk, 



ON BURNING GAS FOR HEAT OR ILLUMINATION. 



By Sii! Jou.v RoiiisoN, K.H., Sec. R.S.E., M.S.A. 



Tht two followivg papers win read, March 1839, before the Society 

 of Arts for Scotland. 



On the best means of Buhninc Gas kor supplyi.vg Heat. 



" Vir ea nostra voco," 

 When carburetted hydrogen eas is employed in producing heat, it 

 is seldom required that it should, at the same time, give out light; 

 the combustion may, therefore, be managed in any way which may be 

 convenient without seeking to preserve the illuminating power.' It 

 appears to have occurred about the same i)eriod to the late Dr. Dun- 

 can and to myself, that, by passing a current of gas, mixed with atmo- 

 spheric air, through a wide vertical tube, having its upper end covered 

 by a diaphragm of wire gauze, and by kindling the mixture as it 

 escaped through the interstices of the wire cloth, a convenient stove 

 might be formed for culinary purposes. Dr. Duncan applied some 

 small apparatus on this principle to pharmaceutical operations in his 

 class-room, and I had ray kitchen furnished with a range of large 

 stoves, which were intended to supersede the use of French charcoal 

 stoves in various culinary processes. In both cases the success has 

 been perfect, and the same principle has since been adopted with ad- 

 vantage in a variety of processes in tlie useful arts, where this neat 

 and cleanly method of applying heat has rendered it a valuable acqui- 

 sition to tlie work-shop. 



The form of the apparatus may be varied in any way to suit tlie 

 particular process to which it is to be applied; as all that is essential 

 is, that a current of tlie mixed gas and air shall rise through wire- 

 clotli, and that the proportion of gas to atmospheric air shall never be 

 so great as to allow of the flame becoming yellow, as, with this pre- 

 caution, the combustion of the carburetted hydrogen will be complete, 

 and no deposit of soot will take place on cold bodies when set over 

 the flames ; the proper quantity of gas in the mixture is easily de- 

 termiued by the stop-cock belonging to each stove. 



For ordinary culinary purposes, the cylinders may be thirty inches 

 long, and three to four inches diameter, and the wire-cloth for the 

 tops should have about thirty wires to the inch. That which is manu- 

 factured for safety-lamps answers well for this purpose. 



Whenever, from accidental injury or decay, a hole takes place in a 

 diaphragm, it is no longer possible to use it : as, when lighted, the 

 flame passes through tlie fracture, and communicates with the jet at 

 the bottom of the cylinder, which then burns like an ordinarv gas-light, 

 and, like it, would blacken the surface of any cold body presented to 

 it. The wire-cloths, if not broken through by violence, will last for 

 montlis although in daily use ; and, if covered by a layer of coarse 

 sand or poundad limestone, vvill continue serviceable for an unlimited 

 period. 



When more intense heat is required than is attainable by the un- 

 aided combustion of the mixed gases, recourse may be had to various 

 forms of blow-pipes; and when a large volume of such flame is to be 

 employed, the current of atmosplieric air may be urged by double bel- 

 lows. A very efiicient apparatus on this principle is to be seen in the 

 laboratory of Dr. D. B. Reid. 



It is to be regretted, that such applications of gas are not more 

 generally known and introduced into work-sliops, as there are nume- 

 rous i)rocesses in the arts in which they would afford facilities to the 

 workman which he can scarcely command by any other means. For 

 example, in the hardening of steel tools, it is well known that a piece 

 of bright steel, when heated to redness in a forge or muffle, is subject 

 to oxidation, and that a black scale remains after hardening, wliicli it 

 is diflicult to remove without some injury to the work, as iii the case 

 of a screw tap; whereas, if the same piece of steel be heated in a 

 flame of the mixed gases, where there is no free oxygen to attack its 

 surface, it may be made and kept red hot without anv injury to its 

 finest edge; it will be discoloured, but without losing much of its 

 polish. The artist has also the advantage of a distinct view of the 

 article while it is being heated, and the power of withdrawing it from 

 the flame the moment it has acquired the proper colour, which, in the 

 hardening of cast steel cutting tools, is of great importance. 



Many attempts have been made to apply carburetted hydrogen and 

 pure hydrogen gases to the purposes of warming buildings, and various 

 jorms of stoves have been proposed, on the understanding, it would 

 appear, that, by applying the flame of the gas to metallic bodies, an 

 increased degree of heat would be communicated by them to the 

 atmosphere around. A little consideration will show,' that however 

 the diistribiition of heat may be modified by such contrivances, there 

 can be no increase of the heating power; and that when a certain 

 measure of gas is fairly burned, the heat evolved into the apartment 



will be the same whether the flame be disposed as a light, or made to 

 play against metallic plates or other combinations of apparatus. In 

 all cases where the products of the combustion are allowed to mix 

 with the atmosphere of the apartment, without provision being made 

 for carrying them off' by ventilation, the erti'cts of such processes must 

 be more or less deleterious to health, according to the proportion 

 these products bear to the mass of air they mix in. On the whole, it 

 may be assumed, that this mode of heating apartments is the most ex- 

 pensive, the least efiicient, and, excepting that by Joyce's charcoal 

 stove, the most insalubrious that can be resorted to', 



0.\ THE BEST .METHOD OF BUHNING GaS FOR THE PUIU'OSE OF 



Ilia'mination. 



The tUeoretical principles on which carburetted hydrogen gas may 

 be used with the best advantage, for the purpose of domestic illumi- 

 nation, have been so well laid down by the late Dr. Turner, and by 

 Dr. Christison, as well as by other chemists, that it would be super- 

 fluous to enter at all on this part of the subject in a paper, the object 

 of which is to give such practical directions for the proper construc- 

 tion and management of gas-fittings, as may lead workmen to give the 

 requisite forms and proportions to the parts, and mav enable the con- 

 sumers to obtain the quantity of light they require, from the smallest 

 practicable expenditure of gas, and with the least possible incon- 

 venience from the products of its combustion. 



It is very generally believed, by workmen and others, that the more 

 freely the current of air is admitted to an argand burner, the better 

 will be the light ; and hence the burners and glass chimneys in ordi- 

 nary use are made in such a way as to favour this view. No practice, 

 however, can be more incorrect, or can lead to less economical results. 

 An attentive observation of what takes place will show, that there ?»• 

 only a certain proportion uf air requindfor the faronrahle combustion of 

 a dtfnite nxasiire of gas. If more air than this due proportion be 

 allowed to pass up the chimney, the size of the flame will be reduced, 

 and the quantity of ligiit diminished ; if, on the other hand, less than 

 the due proportion be admitted, the surface of the flame will be in- 

 creased by elongation, but it will become obscure, and the quantity of 

 light will decrease, owing to the escape of particles of unconsumed 

 carbon. A simple experiment will exemplify this. If the flame of an 

 ordinary argand burner be reduced, by partially shutting the cock, to 

 about half an inch high, the light will be pale and blue, because the 

 supply of air is too great for the small quantity of gas which is issuing. 

 If partial obstruction be given to the access of air, by applying a hand- 

 kerchief under the burner and chimney, it will be found that the size 

 of the flame and the quantity of light emitted will increase until it 

 arrive at a maximum, when, by farther obstruction, the admission of 

 air will be reduced below the proportion required for the burning of 

 the carbon, and the light will diminish. 



It appears, therefore, that the proportionate size and shape of the 

 burners, and the diameter and height of the glass chimneys, are by no 

 means indifferent matters, but that much advantage may be gained or 

 lost by giving them such forms and proportions as may msnre ttie 

 derelopmtnt if tlie maximum degree of light which (he gas is capable of 

 affording. 



As a general rule, it may be considered that in all burners, whether 

 well or ill made, the greatest quantity of light, in proportion to tlie ga^ 

 e.rpendtd, will always be obtained when the flame has been raised as 

 high as it will go without smoking. In proof of this, the following 

 experiment may be made. In any situation where there are three or 

 four burners of the same size, and with similar chimney-glasses, and 

 receiving their gas through a meter (by which the expenditure may 

 be measured), if one of these burners have its flame elevated as high 

 as it can be made to burn without smoking, and if its expenditure per 

 hour be accurately noted on the meter, if the other two or three burn- 

 ers be then lighted, and their flames be so regulated that their united 

 lighting power shall be just equal to the large flame of the first burner, 

 it will then be found, on noting the expenditure, that it is much 

 greater than in the case of the equal light from the single burner, and 

 that the first burner, which gives light equal to two others, consumes 

 but two-thirds of the gas which they do, or, if it be compared with 

 three others giving together an equal degree of light, its consumption 

 will be little more than half of theirs. It follows from this, that when 

 a certain degree of light is required, such a burner should be employed 

 as is capable of giving l/its light and no more, and that it is bad economy 

 to use a more powerful burner with a flame of less than its due height. 

 This rule holds good w itli any number of burners, and is equally true 

 whether they be well or ill made. 



The same rule will apply to the individual jets of an argand burner, 

 as holds in regard to their united effect, and ii, in any burner, the jets 

 be of unequal heights, in consequence of bad drilling of the apertures, 

 or neglect of keeping them free of dirt, the consequence will be, that 



