PRESIDENTIAL ADDRESS. 23 
the equatorial diameter of Saturn as unity, the mean 
distance of the shadow from the edge of the disc was 
found to be 0°13. All the observations were made with 
an equatorial of 17 cm. aperture and 2°02 m. focal length, 
using powers from 157—350 diameters, under atmospheric 
conditions generally very favourable. 
Lost Double Star.—A remarkable chapter of coincidences 
is recorded in No. 7, Vou. xitt of Popular Astronomy, by 
Professor Doolittle, of the Flower Observatory, U.S.A. 
In Sir John Herschel’s first catalogue of double stars, 
No. 165 was described as a 3” pair with a position angle of 
330°, its position being given as R.A. 10h. 26°8m., Dec. 
+ 12° 32’ (1825). In 1878 Professor Burnham directed his 
attention to the pair and recorded position angle as 
205°.3' and distance 2°59". Again in 1901 he observed 
the double with the 40-inch refractor, and obtained a 
measure agreeing with Herschel’s record, but in 1902 he 
could find no trace of the pair observed in the previous 
year, nor of the star measured by him in 1878. Observations 
made in 1905, with the 18-inch refractor of the Flower 
Observatory, failed to reveal the double given by Herschel, 
but showed a very wide faint pair in the exact position 
given by him. Thinking that Professor Burnham in 1901 
might have confused the sign of the declination, Professor 
Doolittle turned his telescope to the same R.A. and Dec. 
minus 12°, and there apparently found exactly the pair 
that was wanted. This seemed to have cleared up the 
mystery; Professor Burnham had in 1901 observed the 
wrong star. A letter from that observer showed, 
however, that this is not the correct explanation. The 
truth is that Herschel made a mistake of exactly one 
hour in recording the R.A. of H.165, and Professor 
Burnham had, unwittingly, made precisely the same 
mistake in 1901. Thus the latest observation of Herschel’s 
