84 



THE CHEMISTRY OF THE SUN. 



[CHAP. 



A word about the modern grating before we proceed. Fraun- 

 hofer's parallel wires were soon replaced by scratching fine lines 

 on a plate of glass through which the light to be analysed was 



FIG. 33. Electric lamp, y, z, wires connecting battery of lifty Grove or Bunsen 

 elements ; G, H, carbon holders ; K, rod which stops a clockwork movement 

 which, when going, makes the poles approach until the current passes ; 

 A, armature of a magnet, which by means of K frees the clockwork when not 

 in contact : E, electro-magnet, around which the current passes when the 

 poles are at a proper distance apart, causing it to attract the armature A. 



made to pass. It has since been found better to reflect the 

 light than to transmit it. 



