16 



INORGANIC EVOLUTION. 



[CHAP. 



we must first use a telescope to collect the light, and then employ a 

 spectroscope. 



- Fig. 13 shows a spectroscope thus attached at the eye-piece end of 

 the great Lick refractor. In astronomical inquiries the same methods 

 of work are employed, and although it will be seen that we are now 

 far beyond the improvised spectroscope with which we began, both in 

 construction and use, no new' principle is involved. 



FIG. 13. A stellar spectroscope attached 'to the Lick equatorial. 



Now if my reader has not hesitated to invest his or her sixpence 

 in a prism, and has had the patience (no other quality is needed) to do 

 what I have suggested, the way is open to read without difficulty most 



