N£VV STARS 161 



aetic process in their photospheres, we may consider this 

 process of light as variable in many ways, without assuming 

 any local or temporary condensatio7is of the celestial ether, 

 or any intervention of the so-called cosmical clouds. It may 

 either occur only once or recur periodically, and either reg-u- 

 larly or irregularly. The electrical processes of light on our 

 earth, which manifest themselves either as thunder-storms 

 in the regions of the air, or as polar effluxes, together with 

 much apparently irregular variation, exhibit nevertheless a 

 certain periodicity dependent both on the seasons of the year 

 and the hours of the day ; and this fact is, indeed, frequent- 

 ly observed in the formation for several consecutive days, 

 during perfectly clear weather, of a small mass of clouds in 

 particular regions of the sky, as is proved by the frequent 

 failures in attempts to observe the culmination of stars. 



The circumstance that almost all these new stars burst 

 forth at once with extreme brilliancy as stars of the first mag- 

 nitude, and even with still stronger scintillation, and that 

 they do not appear, at least to the naked eye, to increase 

 gradually in brightness, is, in my opinion, a singular pecul- 

 iarity, and one well deserving of consideration. Kepler^ at- 

 tached such weiijht to this criterion, that he refuted the idle 

 pretension of Antonius Laurentinus Politianus to having seen 

 the star in Ophiuchus (1604) before Bronowski simply by 

 the circumstance that Laurentinus had said, " Apparuit nova 

 Stella parva et postea de die in diem crescendo apparuit lu- 

 mine non multo inferior Venere, superior Jove." There are 

 only three stars, which may be looked upon in the hght ol 

 exceptions, that did not shine forth at once as of the first 

 magnitude ; viz., the star which appeared in Cygnus in 

 1600, and that in Vulpes in 1670, which were both of the 

 third, and Hind's ne tar in Ophiuchus in 1848, v/hich is 

 of the fifth magnitude. 



It is much to be regretted, as we have already observed, 

 that after the invention of the telescope in the long period 

 of 178 years, only two new stars have been seen, whereas 

 these phenomena have sometimes occurred in such rapid suc- 

 cession, that at the end of the fourth centuiy four were ob- 

 served in twenty-four years ; in the thirteenth century, three 

 in sixty-one years ; and during the era of Tycho Brahe and 

 Kepler, at the end of the sixteenth and beginning of the sev- 

 enteenth centuries, no less than six were observed within a 



* Kepler, De SlcUa Nova in pede Scrp., p. 3. 



