ASTRONOMY. 



27 



great change in the result will be effected by the figures ob- 

 tained from the latter source. The new British calculations 

 give for the value of the sun's parallax 8.76", with a proba- 

 ble error of 0.013". This corresponds to a distance for the 

 sun of 93,300,000 miles, with a probable error of 140,000 miles. 

 The British photographs of the transit of Venus have been 

 twice measured, and are discussed by Captain Tupman. His 

 conclusions are that the English method was fundamentally 

 wrong (as, indeed, was predicted), and the two results (8.25" 

 and 8.08") are of no value, and must be rejected. 



Lord Lindsay has published the second volume of the An- 

 nals of the Dun-Echt Observatory a quarto volume of 212 

 pages. It contains the determination of the solar parallax 

 by observations of J~uno, and a description (with plates) of 

 the heliometer employed. The method employed is the de- 

 termination of the diurnal parallax, and this experiment was 

 tried to determine the advantages or disadvantages of the 

 method. The authors (Lord Lindsay and Mr. D. Gill) think 

 that this method has been shown to be one of the very best, 

 and the resulting solar parallax 8.77"0.041" is regarded as 

 a close approximation, to be subsequently corrected by sim- 

 ilar observations of Mars and asteroids which have been made 

 by Mr. Gill at Ascension Island. The description of the he- 

 liometer, with the investigation of its constants, is very full, 

 and will serve as a manual for similar investigations. It is 

 concluded that it is possible with this instrument to deter- 

 mine the distance of a minor planet relative to two stars 

 with a probable error of less than 0.1". 



THE DISCOVERY OF VULCAN. 



The reports of Professor James C. Watson, of Ann Arbor, 

 Mich., and Mr. Lewis Swift, of Rochester, on their discovery 

 of a new star or stars during the eclipse are given below in 

 the form of letters to the Superintendent of the Naval Ob- 

 servatory, Washington. Subsequent letters give changes in 

 matters of detail, but the most important facts are given be- 

 low. Professor Watson says : 



"I am now able to give you more precise information in 

 reference to my observations of a supposed new planet dur- 

 ing the recent total eclipse of the sun. . . . Before the com- 

 mencement of the eclipse, the adjustment of the equatorial 



