Mr, Herschel’s Catalogue of Double Stars, 41 
24 begins here at 25, and the fame is done with the other 
clafles. 
Moft of the double ftars in my firft colleftion are among the 
number of thofe ftars Which have their places determined in 
Mr. Flamsteed’s extenlive catalogue ; but of this colledtioif 
many are not contained in that author’s work, I have therefore 
adopted a method of pointing them out, which it will be proper 
to defcribe. 
The finder of my refie&or is limited, by aproper diaphragm, 
to a natural field of two degrees of a great circle in diameter. 
The interfedtion of the crofs wires, in the center of it, points 
out one degree ; and by the eye this degree, or the diftance 
from the center to the circumference, may be divided into 
§ , f, 4, and f . Thus we are furnifhed with a meafure which, 
though coarfe, is however fufficiently accurate for the purpofe 
here intended ; and which, if more than two degrees are 
wanted, may be repeated at pleafure. 
In fuch meafures as thefe I have given the diftance of a dou- 
ble ftar, whofe place I wanted to point out, from the neareft 
ftar in Flamsteed’s Catalogue. And fince, befides the 
diftance, it is alfo required to have its pofition with regard to 
the ftar thus referred to, I have ufed the neighbouring ftars for 
the purpofe of pointing it out. 
The ufefulnefs of this method is fo extenfive, that I fhall be 
a little more particular in defcribing its application. When a 
ftar is thus pointed out, as for inftance the %2d in the frit clafs, 
where it is faid, “ About £ degree f. preceding the 44th Lyncis, 
ts in a line parallel to 0 Urfte majoris and the 39th Lyncis we 
are to apply one eye to the finder, and placing the 44th Lyncis 
into the center of the field, we are to look at 9 Urfas majorir 
and the 39th Lyncis in the heavens with the other eye by the 
Vol. LXXV. G fide 
