2 
Pofitions and Magnitudes of the Fixed Stars, &c. 135 
In obferving in this way it is manifeft, that the places of 
fuch ftars as happen to be under or very near any one of the 
wires, muft be more to be depended upon, than of what are in 
the intermediate fpaces, efpecially if towards the edges of the 
field: fo alfo what are neareft to the centre, becaufe better de- 
fined, and more within the reach of one wire or another. For 
this reafon, different {tars in the fame fet muft fucceffively be 
made central, or brought towards one of the wires, where any 
fufpicion arifes of a miftake, in order to approach nearer to a 
certainty: but if the ftand of the telefcope be tolerably well 
adjufted and fixed in its place, that is foon done. 
In fuch a glafs it is very feldom that light is wanting Gaff 
cient to difcern the wires. When an illuminator is required, 
I find, that for this purpofe, where you with to fee every {mall 
{tar you can, a piece of card or white pafte-board, projecting, 
on one fide beyond the tube, and which may be brought for- 
ward occafionally, is better than one of any other kind. By 
cutting acrofs a {mall fegment of the object-gla{s, it throws a 
fufficient light down the tube, though a candle is at a great 
diftance ; and one may lofe fight of that falfe glare when one 
pleafes, by drawing back the head, and moving the eye a little 
fide-ways, and then one fees the {maller flars juft as well as if 
no iljuminator were. there. 
This then is the method I would recommend to the pm CHeal 
aftronomer, for becoming acquainted with the appearance of 
the ftars, and fetting a’ watch over the heavenly motions. 
After a very few trials, every one would find this eafy. And if 
each perfon of every rank among aftronomers would take a 
conftellation or two under his care, the numbers who could 
undertake it in this: way would compenfate for the defects of 
a plan which cannot afpire at’ great accuracy. ‘The labour of 
“Vou: LXXIV. Bb | it, 
