398 Sir John Robison oh the best Method of 



as, besides intex-cepting a considerable portion of the light, 

 they prevent the consumers from observing whether the burn- 

 ers and glasses be in good order, and pei'forming propex'ly. 



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 light- 

 ing lamps, the stopcock be opened suddenly, and a burst of 

 gas be permitted to escape before the match be applied to 

 light it, then a strong puff 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, the glasses are taken off and wiped every day, and be- 

 fore they are put on again, the match 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 flame, 

 the glasses being then put on quite straight, the stopcocks 

 are gently tiurned, until the flames stand at three inches 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 

 situations where it is difficult to get at 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 some- 

 times 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 standing on 

 the floor, and to malvc their levers so long that their move- 

 ments may be easily gi'aduated. The cocks and levers may 

 easily be designed 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 precau- 



