194 



BURNERS. 

 Fig. 41. 



their flames will just touch ; both will immediately burn with a white light, 

 and the quantity be increased more than a third, which can easily be proved 

 by the test of relative shadows with the photometer. A greater quantity of 

 light can therefore be produced from the same quantity of gas by using this 

 description of burner. 



Fig. 42. represents a burner that was contrived by Mr. Clegg in 1813, to 

 silence some objections that were raised by the Insurance Companies against 

 the use of gas, and mentioned at page 1 7. It is too expensive for general use, 

 but may be applied in vaults and confined places, where the escape of gas 

 from an open lamp might cause an explosion. 



A A is the drilled ring, from which the gas is burnt. 



B is the inlet for the gas. 



C is a valve which closes when the brass tube D cools, and prevents the 

 escape of the gas. 



When the lamp is to be lighted the valve is lifted by pressing the button E 

 upwards with the thumb ; the expansion of the rod D, by the heat of the 

 flame, retains it in this position, and when the flame is extinguished the valve 

 is suffered to fall on to its seat by the contraction of the rod D. The form of 

 the burner itself may be varied in any way. The woodcut represents that in 

 which the experimental lamp was constructed. 



