81 



REPORT 1870. 



In the Table of the results, the times of the observations are those 

 stated by the observers from the best approximations to Greenwich time 

 within their reach, differing from each other occasionally by one or two 

 minutes. The number of the meteors visible, chiefly of the brighter class, in 

 the fuU-moonlight of the 10th of August last having been small, and regard 

 being paid to the condition that the parallax (fig. 4) of the observed meteor- 

 tracks should be as nearly as possible in the same direction as the base-line 

 joining two corresponding stations upon the map (fig. 3 represents the relative 

 situations of the observers), the errors of time from true Greenwich time at 

 the different stations were very easily detected, and were found to be nearly 



Fig. 4. 



Adopted apparent patbs of sixteen shooting-stars doubly observed in England, August 

 oth-llth 1870 at (B.) Birmingham, (H.) Hawkhurst, (Hy.) Hay, South Wales, (L.) 

 London, (M.) Manchester, (T.) East Tisted, Hants, (Y.) York. 



constant throughout the observations. The names of the stations are given, 

 for shortness, in figs. 3 and 4, by their initials ; and in the latter figure the 

 observations have been so far adjusted to each other as to satisfy, by very 

 slight changes in the majority of the observations, the condition of a parallel 

 displacement of the meteor-tracks in the direction of a base-line joining the 

 observers' stations. 



The_ observed length of the path being, in general, most affected by this 

 preliminary adjustment, a corresponding alteration of the observed duration 

 of the meteor's flight was cakulated, and entered in a Table as the " adopted 

 duration," from the average of which, at the two stations, the velocities of 

 twelve of the shooting-stars have been obtained. The time of visibility of 



