Clifton College Scientific Society. 



87 



Indium was discovered in 1864. Its spectrum is characterised 

 by two lines only, one in the violet and the other in the blue. 



Whenever we wi.sh to analyse metals proper or heavy metals, it 

 becomes a more difficult matter, as the heat of the Bunsen's flame 

 will in most cases be found not to be strong enough. We have 

 recourse then to electricity. By means of an induction-coil and a 

 battery we can obtain a spark sufficiently strong to volatilise the 

 metals. But how does this take place ? It was fully proved by 

 Faraday that electric sparks consisted partly of the material of the 

 poles, and partly of the air and moisture of the air in a high state 

 of ignition. In this way we may also get the spectrum of the gases 

 constituting our atmosphere. Every gas gives lines peculiar to 

 itself ; and if there is a considerable amount of catbouic dioxide 

 in the air, we may even get the spectrum of this. Wheatstone 

 has drawn several of the lines which various metals give, altiiough 

 there are a very great number. Vb signifies very bright, h bright, 

 f faint, and vf very faint. 



BLUE 



BLUISH.. 



Green 



Green 



Green 



Orange .... 

 Red 



