Observations of the apparent distances and positions of 380 
double and triple Stars , made in the years 1821, 1822, and 
1823, and compared with those of other Astronomers ; to- 
gether with an account of such changes as appear to have taken 
place in them since their first discovery . Also a description of 
a Five-feet Equatorial Instrument employed in the observations . 
.By John Frederick William Herschel, Esq. F. R. S. and 
James South, Esq. F. R. S. 
Read January 15, 1824. 
The frequent and exact determination of the apparent dis- 
tances and positions of such double stars, as are sufficiently 
close to be easily measured with micrometers and high mag- 
nifying powers, was suggested by Sir William Herschel, 
more than forty years ago, as an enquiry likely to lead to 
interesting results, and which has, in fact, in his hands, led 
to the creation of a new department of physical astronomy, 
and to the discovery of a class of phenomena in the sidereal 
heavens referable to the agency of attractive forces, and 
analogous to those produced by gravity within the limits of 
our own system. The immediate object with which the en- 
quiry was commenced, the determination of the existence and 
amount of annual parallax, was soon lost sight of in the more 
extensive views of the construction of the universe which 
unfolded themselves as it advanced, and has not since been 
resumed ; though, from the extreme precision of which it will 
appear in the course of this paper such measurements are 
susceptible, owing to the refinements of modern instrument- 
making ( a precision not to be looked for in any other class 
MDCCCXXIV. B 
