162 



lead Dr. Olbers to the conclusion announced in a succeeding No. (284) 

 that observations of this kind are adequate for the complete determi- 

 nation of longitudes of places. By means of twelve coincidences on 

 the same night, Prof. Boguslawski found the Breslaw Observatory to 

 be 28m 22s.07 east of Altona, differing less than a second from that 

 which had been previously adopted. 



As the subject of priority in this inquiry might be considered im- 

 portant, Mr. Walker deemed it his duty to communicate the substance 

 of a letter from Prof. Alexander, of Princeton College, New Jersey, 

 dated January 14th 1839, in which is contained the result Of seven 

 coincidences of observations of meteors, made 25th Nov. 1835, by 

 Messrs. A. D. Bache and J. P. Espy, at the house of Prof. Bache, in 

 Philadelphia, and by Professors Henry and Alexander, at the Philoso- 

 phical Hall, 0.1s. east of Nassau Hall, College of New Jersey, at 

 Princeton. As the time referred to by the Philadelphia observers is 

 that of the University of Pennsylvania, which is about 0.7s, west of 

 the State House, Philadelphia, the differences of longitude, given by 

 Prof. Alexander, have been diminished by 0.6s. to reduce them to 

 the State House , Philadelphia, and Nassau Hall, Princeton. The re- 

 sults are contained in the table. The time of the disappearance of 

 the meteors was noted. 



Meteor. 



a 

 b 

 c 

 d 

 e 

 f 

 g 



N. Hall, East of 

 State House. 



Comparative 

 Weight. 



Observers. 



-{-2m. 0.45sec. 

 +2 „ 0.30 „ 

 -f 1 ,,59.20 „ 

 +2„ 20 „ 

 +2 „ 1.00 „ 

 +2 „ 0.80 „ 

 +2 „ 2.60 „ 



1 

 1 



0.5 

 1 

 1 

 1 



0.5 



Espy and Alexander. 



" and " and Henry, 



" and Henry, 



" and " 

 Bache and " 



" and Alexander, 

 Espy and Henry. 



Mean according to weights + 2 m 0.61 sec. 



S. House, W. of Greenwich — 5k. „ 39.12 „ 



N. Hall, W. of Greenwich — 4„ 58 „ 38.51,, No. 1. 



In order to judge of the degree of precision of this result, an extract 

 of a letter from Robert Treat Paine, Esq. dated June 10th, 1839, was 

 read, giving his determination of the same by transportation of three 

 chronometers in May last, from Princeton to Castle Garden, New 

 York, and thence to Boston, as follows : 



State House, Boston — 4h. 44m. 16.60sec. 

 Castle Garden, West — 11 „ 46.33 „ 



Nassau Hall, W. of C. Garden — 2 „ 35.14 „ 



Nassau Hall, W. of Greenwich — 4„ 58 „ 38.07 „ No. 2. 



