1841.1 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



195 



■when the fliime is raised until the jet from the widest hole reaches the 

 most advantageous height, those from the obstructed holes will be 

 consuming the gas at a disadvantage, which n'M be greater or less 

 according to circumstances, but will always be of greater amount than 

 is generally supposed. 



The experiments made by Drs. Turner and Christison serve to 

 show, that much smaller chimneys than those usually employed are 

 required to burn the gas to the best advantage. Unfortunately, how- 

 ever, the dimensions most favourable to economy in one respect, are 

 beyond the limits of economy in another; and when the glasses are 

 made small enough in diameter to obtain the maximum of illuminating 

 effect, they are liable to be softened by the heat; or to be cracked, i/ 

 ■not accurattlij centered. A compromise between the two evils must 

 therefore be made, and if this be judiciously done, a gnat improve- 

 ment on the usual routine practice ma;/ he effected, a more beautiful and 

 steady light he obldined at a less cost, and our domestic comfort he in- 

 creased, by the diminution of the heat and (Jjlurta of the gan. 



For practical purposes, therefore, the following directions may be 

 observed. 



Whatever diameter is given to the burner, the glass chimney should 

 Eot exceed it by more than half an inch at the utmost. If the burner 

 be less than three fourths of an inch in diameter, the chimney glass 

 should not exceed Ij inch in internal diameter, hi any case, its 

 height should be no more than four inches above the mouth of the 

 burner from which the jets spring. 



The smallness of the interval which is in this way allowed between 

 the flame and the glass, renders it necessary that the workmanship of 

 the supporting gallery be accurate, in order that the chimnty may be 

 held perpendicular, and truly concentric nuik the fame. Gas-fitters 

 rarely give sufficient attention to this important point, and a large 

 share of the expense from broken glasses is ow ing to defects in this 

 particular. 



In the ordinary mountings, the gallery is put on the burner, which 

 it seldom fits accurately, the glass likewise rarely fits tight into the 

 socket of the gallery, and from these two causes, it is often so much 

 off the centre, or so f^ar from being upright, that the fiame cannot be 

 raised to a jiroper height without risk of breaking it. This risk may 

 be greatly diminished by a little change in the disposition of the 

 burner and gallery. Instead of hanging the gallery on the burner, it 

 should be placed beneath it, and fixed by screwing down the burner 

 on it. In this case, it is necessary to give the gallery an increased 

 diameter, as the air, both for the inside and the outside of the flame, 

 must enter through its ribs. The burners should also be made conical 

 instead of cylindrical ; but this is not so important as drilling them 

 with numerous holes — at least double the number usually allowed, as 

 the closer they are the better, the expenditure being regulated by the 

 stopcock, and not by the number of holes. 



In making the galleries, great attention should be paid to having 

 the rim and seat for the glass truly concentric with the hole through 

 which the nozzle-screw, on which the burner is fixed, passes ; the 

 workmen should have a solid wooden chuck of the size of the bells of 

 the chimney-glasses, and should chuck the galleries on it, in order to 

 drill the aperture through which the nozzle-screw is to pass. The 

 outside and inside faces of this hole should at the same time be turned 

 true, as, if this be done with the proper care, the glass, the burner, 

 and the gallery, will all be true to the same axis, when they are put 

 together and screwed up. The hole through the gallery should not 

 be tapped, as the burner is sufficient fixture for it when screwed down 

 over it. If this part of the work be well executed, even an indiffe- 

 rently made burner will perform well, and if it be ill done, the best 

 burner will appear defective, and be liable to break the glasses. 



The arrangement of burner and gallery here recommended is not 

 incompatible with the use of plain cylindric glasses, but it will be 

 found better to use what is sometimes called the French-shaped chim- 

 neys, that is, those which are used with the common argand oil-lamps. 

 The wideness of their mouths gives them a firm seat in the gallery, 

 and if the length of the bell, or wide portion of the glass, be such that 

 the neck or choke shall be on the level of the lip of the burner, and 

 the upper )nirt of the glass be four inches to four inches and a half 

 long, then a favourable result will be obtained. It is expedient to 

 obscure the lower part or bell of the glass, as the burner is thereby 

 concealed, and the flame appears to rise out of a thick wax-candle. 

 No moon-shades should ever be used, as, besides intercepting a con- 

 siderable portion of the light, they prevent the consumers from ob- 

 serving whether the burners and glasses be in good order, and per- 

 forming properly. 



It is pretty generally imagined that the smoking of ceilings is 

 occasioned by impurity in the gas, whereas in this case there is no 

 connection between the deposition of soot and the quality of the gas. 

 The evil arises either from the flame being raised so high that some 



of its forked points give out smoke, or more frequently from a careless 

 mode of lighting. If, when lighting lamps, the stopcock be opened 

 suddenly, and a burst of gas be permitted to escape btfore the match 

 be applied to light it, then a strong ])uff follows the lighting of each 

 burner, and a cloud of black smoke rises to the ceiling. This, in many 

 houses and shops, is repeated daily, and the inevitable consequence is 

 a blackened ceiling. In some well-regulated houses, tlie glasses are 

 taken off and wiped every day, and before they are put on again, the 

 mutch is applied to the lip of the burner, and the stopcock cautiously 

 opened, so that no more gas escapes than is sufficient to make a ring of 

 blue fame ; the glasses being then put on quite straight, the stopcocks 

 are gently turned, until the flames stand at three int-lies high, When 

 this is done, few chimney-glasses will be broken, and the ceilings will 

 not be blackened for years. 



Gas-fitters and lamp-makers generally put the stopcocks in situ- 

 ations where it is diflScut to get al them, and they make their heads 

 so small that, if they be in the least degree stiff, it is not easy to turn 

 them gradually: hence, when a little force is applied, they move by 

 starts, and the flame is sometimes raised too high, or, instead of being 

 a little lowered, is altogether extinguished. The remedy for this 

 inconvenience is to make the cocks easily accessible to a person stand- 

 ing on the floor, and to make their levers so long that their movements 

 may be easily graduated. The cocks and levers may easily be de- 

 signed so as to form part of the ornamental work of the lamps. 



The argand burner being the most perfect and economical which 

 can be used, unless where small portions of light are required, it is 

 unnecessary to say any thing of the bat-wings and other fancy burners, 

 especially as the only precaution to be taken with them, is to take 

 c.ire not to raise them so high as to smoke, and never to use two or 

 more low flames, when the same degree of light can he got from one 

 flame burning at its most effective height. 



A mode of supplving argand burners with a current of heated air 

 lias been lately proposed in Paris, and much praised in London. This 

 is effected by having an outer glass of a diameter a little larger than 

 the inner one. This out r glass reaches farther down than the bottom 

 of the burner, and is closed below by a metal plate ; the air for the 

 supply of the flame is made to pass down between the outer and inner 

 glasses, where it gets heated; it then enters the inner glass and the 

 centre aperture of the burner, and passing upwards, supports the com- 

 bustion of the gas in the usual way. There is no doubt that, by this 

 arrangement, a considerable impro^ ement may be made in cases where 

 ill-made b\u-ners, with wide and tall chimney-glasses are employed ; 

 but if the experiment be tried with b\n-ners and glasses proportioned 

 in the way recommended above, it will be found that no advantage is 

 gained, and that the maximum effect has been attained by a simpler 

 apparatus. 



Before quitting the subject of burners, it may be right to advert to 

 a frequent cause of disappointment in their performance. The per- 

 fection of an argand burner is, that the fame arising from it should 

 appear in a continuous cylindric sheet, with a smooth upper edge, and 

 without forking points. This is sometimes very difficult of attainment, 

 however carefully the jet-holes may be gauged by the pricker. There 

 are two causes for this irregularity; one is, that, if the drill which is 

 used be blunt, a little blaze is pushed aside by it when it is forced 

 through the plate in which the jet holes are pierced; this blaze ad- 

 heres to the edges of the hole, and interferes with the passage of the 

 gas, and being unequal in its effects, renders the flame forked. The 

 other cause is, that the insitle of the burner is seldom turned true, and 

 that the shoulder in which the pierced disk rests, is not of equal 

 width all round, and sometimes may be so thick in some places, that 

 the drill, when it gets through the disk, strikes against the shoulder; 

 this likewise interferes with the issue of the gas. To avoid these 

 causes of irregularity, the following precautions are essential. When 

 the seat for the disk is turned out, the inside space between the inner 

 and outer walls of the burner should be turned true for a quarter of 

 an inch inwards, and no more shoulder should be left than just enough 

 to su|)port the disk in its place. The disk should then be put into its 

 seat, but not finally fixed. The requisite number of holes should then 

 be drilled in it, and slightly counter-sunk to take off the barb. The 

 disk should then be reversed (that is to say, the counter-sunk face 

 should be put inwards), and finally fixed in its place. The blaze which 

 may have been pushed through with the drill will now be on the out- 

 side, and may be easily removed by the file, or by a slight counter- 

 sinking, which is the preferable manner, as the smooth-edged holes 

 will keep longer clean than those with a sharp arras, the application 

 of an old tooth-brush being sufficient to keep them in good order. 



The above observations apply chiefly to the illumination of the in- 

 teriors of buildings, and it may be proper to notice the circumstances 

 which require to be attended to in lights which, being placed exter- 

 nally, are in some degree exposed to the weather. The most im- 



