3 CO Mr. HERSCHEL OH tht 
eftimatioas of the fame eye when accuftbmed to this kind of 
judgement. 
I have divided the double flats into feveral different claffes. 
In the fir ft I have placed all thofe which require indeed a very 
fuperior telefcope, the utmoft clearnels of air, and every other 
favourable circumftance to be leen at all, or well enough to 
judge of them. They teemed to me on that account to delerve 
a feparate place, that an obferver might not condemn his in- 
flrument or his eye if he thould not be fuccefsful in diftin- 
guifhing them. 
As thefe are fome of the fineft, moft minute, and moft de- 
licate objects of vifion I ever beheld, I fhall be happy to hear 
that my obfervations have been verified by other perfons, which 
I make no doubt the curious in aftronomy will foon undertake. 
I thould obferve, that fince it will require no common ftretch 
of power and diftin&nefs to fee thefe double ftars, it will there- 
fore not be amifs to go gradually through a few preparatory 
Ifeps of vifion, fuch as the following : when v\ Coronas borealis 
'(one of the moft minute double ftars) is propofed to be viewed, 
let the telefcope be fome time before directed to ^ Geminorum, 
or if not in view to either of the following ftars, £ Aquarii, 
[a, Draconis, f Herculis, « Pifcium, or the curious double- 
double ftar e Lyras.. Thefe thould be kept in view for a conli- 
derable time, that the eye may acquire the habit of feeing fuch 
objects well and diftinTly. The obferver may next proceed to 
£ Urfas majoris, and the beautiful treble, ftar in Monoceros’s 
light fore- foot ; after thele to i Bootis, which is a fine minia- 
ture of a. Geminorum, to the ftar preceding a Orionis, and to 
n Orionis. By this time both the eye and the telelcope will be 
prepared for a ftill finer picture, which is y\ Coronas borealis. It 
will be in vain to attempt this latter if all the former, at leaft 
z, • i Bootis, 
