THE TWO COMETS OF THE YEAR 1868. 163 



powerful telescopes in use have been fitted with them. 

 We hear also, that the giant reflector of the Parsons- 

 town Observatory commonly known as the Sosse tele- 

 scope has been armed with a spectroscope especially 

 constructed for the purpose by Mr. Browning, F.R.A.S., 

 the optician. Not only in England, but at the princi- 

 pal Continental observatories, spectroscopic work is in 

 progress, and observers are daily becoming more and 

 more familiar with the powers of the new analysis. 

 Stars which are far too small to be viewed by the 

 naked eye have already been examined with the spec- 

 troscope. The Padre Secchi at Rome has just pub- 

 lished a list of minute red stars thus examined. It is 

 such delicate work as this which will fit observers to 

 deal with the difficulties involved in the spectroscopic 

 analysis of comets. 



We shall see when we come to deal with the second 

 cometof the year 1868, that wehave yet better reason than 

 the analysis of Brorsen's comet has afforded, for hoping 

 that before long we may have interesting and exact 

 information respecting the structure of these mysterious 

 wanderers. We may even hope to gain some know- 

 ledge respecting the purposes which comets subserve in 

 the economy of the solar and sidereal systems. 



PAET II. WINNECKE'S COMET. 



IN the preceding pages I have described the principal 

 features presented by comets as they approach and pass 

 away from the neighbourhood of the sun. The various 



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