in.] COLOURED FLAMES. 29 



of ordinary gas and air ; the gas being supplied through the 

 smaller tube inserted into the lower end of the larger one in 

 which the mixture takes place as shown in fig. 12. The gas 

 should be lit by holding a match some three inches above the 

 upper orifice of the wide tube. One end of the platinum wire 

 may be fused into the piece of glass tubing, and the other 

 twisted into a loop fine enough to hold some common salt in the 

 flame. A piece of coke or charcoal soaked in salt and water 



FIG. 13. Method of inserting platinum wire and salt into flame. 



will do almost as well. This tube may be supported by a 

 piece of wood, after the fashion of Fig. 13. The Bunseu burner 

 will give us a very hot bluish flame into which the loop of 

 platinum containing common salt (sodic chloride) may be 

 inserted, as shown in the accompanying woodcut. We shall 

 get a brilliant yellow flame which is worth notice on its own 

 account. 



Instead of this improvised Bunsen burner we may use as 

 the old observers before the introduction of gas were compelled 



