THE TELESPECTBOSCOPE. 



99 



bring now a spot, and now one of the brighter portions of the 

 sun, on to the slit. If there be any difference between the 

 spectrum of the spot and the spectrum of the general surface of 

 the sun, such difference will be thus observed at once, and the 

 differences are in fact very striking 



Such an instrument, compounded of the telescope and spectro- 

 scope, has been named a telespectroscope. 



FIG. 37. The eyepiece end of the Newall refractor (of 25 inches aperture) with 

 spectroscope attached. 



The next point to engage our attention is the change in the 

 phenomena produced by this change in the method of observa- 

 tion. We will first deal with spots. 



3. Spot Spectra. 



When an image of a sun-spot has been thrown on the slit of 

 the spectroscope in the manner described, it shows itself in the 



H 2 



