ASTRONOMY, 197 



each instrument from each pair of stars (Safibrd's catalogue), is given 

 iu detail, and compared with the results of i)ast .yearg. 



The mean of all the observations for latitude made in 1884, is as fol- 

 lows, all pairs and observations having equal weight: 



Zenith telescope by Wurdemann (190 observations on 43 pairs) gives 

 40O 47' 20".47. 



Zenith telescope, by Lingke (333 observations on 54 pairs) gives 40° 

 47' 20".92. 



Grand mean for observations of 1884, giving observations and instru- 

 ments equal weight, is 40° 47' 20".75. 



The results of previous years are added for comi)arison (l"=10l 

 feet :) 



Transferred from old observatory 40° 47' 21". 70 Az 0".57o 



In 1880 (32G observations of 84 pairs) 21".59 ± 0".08'i 



1881 (591 observations of 104 pairs) 21".47 



1882 (235 observations of GO pairs) 21".37 



1883 (497 observations of 118 pairs) 21".15 



1884 (523 observations of 89 pairs) 20". 75 



" The grand mean of 2,172 observations made at the new observatory 

 during the past five years is 40° 47' 21".23 ; but it will be noticed that 

 there has been a steady reduction in the yearly means during this en- 

 tire period, and that the less exact determination at the old observatory 

 indicates a change in the same direction." 



Although the nature of the observations and the small absolute value 

 of the quantity' in question render it quite possible to attribute this 

 solely to errors of observation, the fact is, nevertheless, an extremely 

 interesting one in its relation to the question of the variability of terres- 

 trial latitudes, and deserves further examination. 



Longitude was determined by lunar culminations, and the errors of 

 each separate result compared with the known (telegraphic) longitude 

 were: 7«.5; 3G.0; 2.2; 15.1; 3.8; 10.4; 14.G; 5.5. 



Longitudes by lunar distances were also determined with errors as 

 below: 1G«.5; 12.9; 7.3; G.7 ; 4G.4; 39.7; 23.9; 11.7. 



Auroral displays are regularly noted by the sentinels, and an inter- 

 esting table of the results since 1870 is given. 



What has been given as an abstract of one year's work in only one 

 department of this school of ai)i)lication for young engineer ofdcers is 

 sufficient to show that we have at present no better school of practical 

 astronomy in America. 



Yale (Jolleije Observatory. — The observatory in Yale College is now 

 without a director, Professor Kewton having resigned that otfice last 

 May, being now the secretary to the board of managers, whose presi- 

 dent is Dr. Porter, the president of the college. The points of most 

 importance iu the secretary's report for the year 1S84 relate to the pho- 

 tograpuo of the late transit of Venus taken by jMr. Willsou, and now iu 



