WeUi7igtoii I'iiilosophical Society. 9 



regarding their constitution and structure upon some of which it was hoped light 

 would be thrown by improved methods and appliances. The spectroscope had re- 

 vealed hydrogen and hydiocarbons in the tails of comets. But the comets, though 

 of large volume, were insignificant in mass. Bulking sometimes hundreds of tinies 

 as large as the sun. they contained less substance than an asteroid ten miles in 

 ■diameter. Their tenuity was almost inconceivable— a state of rarefaction exceeding 

 the most perfect vacuum that could be produced artificially. Comets possessed a 

 light of their own beside that reflected from the sun, but 'its nature was not yet 

 determined. 



Both papers were fully illustrated with lantern-slides, including a fine series of 

 photographs of the approaching comot taken at the Meeanee Observatory, Napier. 



Si'EciAi. Meeting: 30f/i May.. J9J0. 



Ml-. A. Hamilton, President, in the chair. 



rajyer.— '' The Astronomical Importance of the Theory of the Third 

 Jfody," by Professor A. W. Bickerton. 



The author delivered a lecture on the astronomical importance of the theory 

 •of the third body before n largely attended meeting of the Society, and lucidly 

 explained the formation of a third body from the partial collision of two celestial 

 bodies. He said astronomers were now all agreed in recognizing the existence of 

 "dead suns," and grazing-collisions among the stars, but were not in agreement 

 as to the dynamic and physical changes produced by such collisions. The common 

 assumption was that the two bpdies concerned were enormously increased in 

 temperature by collision; he held, on the contrary, that they were' heated only to 

 a comparatively slight extent, but that the third body, struck off in the collision, 

 w;i,s heated to an enormous temperature. This third body had many times the 

 energy of ;;ny other equal mass, and was capable of producing very extraordinary 

 phenomena. Astronomers had missed the idea of the third body, as no reference 

 could be found to it in any standard astronomical work, so that the idea had not 

 presented itself to them sufficiently for them to speak about it. The lecturer 

 entered minutely into the vast energies involved, and defined a new term necessary 

 for any easy understanding of the forces involved — "kinetol," this being propor- 

 tional to the reciprocal of the atomic weight : thus the kinetols of hydrogen and 

 oxygen are as 16 : 1. The lecturer had taken up the problems more than thirty 

 years ago. not as an astronomer or astrophysicist, but as an engineer with a know- 

 ledge of thermodynamics.* He had stated his problems and worked out their 

 solutions, placing his results before astronomers for examination in the light of 

 a.ctual research. He found that the great works on astronomy contained many facts 

 that could only, in his opinion, be explained by his theory ; this was notably the 

 case ill spectrum analysis. 



Mr. A. C. Clifford moved a vote of thanks to Professor Bickerton, and instanced 

 various phenomena which were still a puzzle to astronomers and which this theory 

 seem.ed to explain. 



Dr. Kennedy, F.R.A.S., who seconded the motion, was unable to follow the 

 theory in all points, yet recognized that Professor Bickerton had devised an 

 admirable working theory, worthy of being put to the test by astronomers and 

 investigators into astrophysics. The lecturer had been too modest to mention one 

 important fact^ — his anticipations had been proved in the recorded spectrum of Nova 

 Aurigae. which agreed with predictions made thirteen years previously. The 

 theory deserved much more attention from leading astronomers than it had received 

 in the past. 



The President said he would be very pleased if the Society could help to bring 

 the theory prominently before the astronomical world, and a recommendation might 

 be made to the New Zealand Institute to help the matter forward. 



The vote of thanks was carried amid hearty applause. 



*S(e Trans. N.Z. Inst., 1878, 1879, 1880. 



