REMARKS ON THE DUDLEY OBSERVATORY 

 OBSERVATIONS OF THE TRANSIT OF MER- 

 CURY, MAY 6, 1878. 



By Lewis Boss, 



Director of the Dudley Observatory. 

 [Read before the Albany Institute Mav 28, 1878.] 



The transit of Mercury which occurred ou the sixth of 

 this month has attracted a great deal of attention in the 

 United States. Its accurate observation was felt to be 

 important not only in its relation to the situation of Mer- 

 cury in its orbit and the physical condition of the planet, 

 but also, as affording an opportunity for many inexperienced 

 observers to put themselves in training for the important 

 transit of Venus which will be visible from this part of 

 the world in 1882. In view of this general interest I 

 venture to present to the Institute a more extended notice 

 of the Dudley Observatory observations than I should 

 otherwise have deemed proper. 



In these observations, the thirteen inch equatorial was 

 used at the Observatory; and in order to increase the 

 chances of success, a party was sent from the Observatory 

 to the coast survey station " Helderberg," about fifteen 

 miles west from Albany. As will appear from the appended 

 report of Assistant Landreth, who was in charge, the obser- 

 vations of the party were successful. At the Observatory, 

 my own observations of contact were much affected by the 

 bad state of the air in the morning, and wholly prevented 

 by clouds in the afternoon. 



For some days preceding the transit, the weather had 

 been generally stormy, and on the day before there was a 

 copious cold rain nearly all day, with a sudden clearing in 



