466 Transactions. — Miscellaneoiis . 



some time ; they would spin, and show occasionally their hot 

 and scarred sides. Were they moving in the line of sight 

 they would have their spectral lines displaced — those of the 

 advancing body towards the violet, and of the retreating body 

 towards the red. 



The middle body would be made up from the two original 

 bodies, each of which in retreating would entangle highly- 

 heated matter from the other ; hence almost all the spectral 

 lines would be identical for the three bodies, and, as the three 

 spectra would overlap, almost all the lines w^ould be triple. 



The total light from the planetary nebula would be very 

 feeble, and, if the two wounded suns presented to us their dark 

 sides, the star would nearly disappear, reappearing as the rota- 

 tion continued. 



To put the matter into a few words : A grazing impact 

 generally produces three bodies, a temporary and two variable 

 stars, the temporary star becoming a planetary nebula, and 

 then, as a rule, disappearing; the two variables showing 

 variability for periods ranging from a few years to possibly 

 many centuries, and in about half the cases becoming double 

 stars. 



We will now compare this statement of the results of im- 

 pact, as read in my first papers before the Institute, with the 

 observations on Nova Auriga. 



The new star was triple. As the result of his study of 

 eighty-five observers, Alfred Taylor sums up that there was 

 no doubt of that. Professor Vogel gives the velocity of 

 the three bodies as 420, 300, and 23 miles per second respec- 

 tively. My paper in 1878 showed that when a pair of stars 

 impact the two stars will leave each other, and a third will 

 be produced between them. In 1879 my papers w^ere illus- 

 trated by diagrams, one of which showed the three bodies 

 and the character of their motions as already mentioned, the 

 initial velocity being 500 miles per second. 



The new star showed remarkable fluctuations of light, and 

 almost absolutely disappeared, so that for several months it 

 was not looked for. It was accidentally rediscovered, and 

 found to be of the tenth magnitude. In my papers I called 

 attention to the fact that the central star would increase in 

 intensity and then slowly and steadily diminish ; that the two 

 sheared stars would recover their sphericity, would pulsate, 

 and would also rotate, giving us extraordinary fluctuations of 

 light. If the dark sides of each body were presented to us at 

 once the star would obviously disappear altogether, supposing 

 the central body to have dissipated. 



Astronomers incessantly call attention to the fact of the 

 spectrum of all three bodies being identical. Father Sid- 

 greaves is so amazed at this coincidence, and at there being 



