[. 51 ] 



X.— NOTES ON THE TEANSIT OF VENUS, AS OBSERVED AT 

 STREETE, CO. WESTMEATH. By W. E. WILSON, E.E.S.A. 



[Eead, December 18, 1882.] 



The 6th was cloudless throughout. The error of the Observatory 

 mean time clock was got by a transit of the sun at noon. The 

 24-inch reflector was stopped down to 12 inches, and a polarizing 

 eye-piece used. The 4-inch finder was also used with a power of 75. 

 The first contact was observed at 1^ SI"" 54' Streete mean time. 

 I was not quite sure of the exact position- angle that contact would 

 take place at, so that I am sure the above time is a few seconds late. 

 The time I calculated for first contact was 1^ 31"^ 14' S. M. T. At 

 1^ 38™ the entire disc of Venus could be seen against the corona. 

 The planet seemed much darker than the corona, and was sur- 

 rounded by a thin ring of silvery light. This ring was much 

 brighter at the place marked in the following diagram by ^. I 

 suppose it was caused by a bank of clouds in the planet's atmos- 

 phere. 



Internal contact occurred at 1^ 52°^ 14vS. M. T., and is, I be- 

 lieve, very close to the calculated time. There was no appearance 

 of " black drop." The two cusps of light were almost quite sharp, 

 and gradually closed up until they touched. As soon as Yenus 

 was well on the disc I mounted the spectroscope, and made a care- 

 ful search for any absorption lines in the planet's atmosphere. 



