r 32 Mr, jeaurat’s Account of 
very fmall ftars, for in this conftru<ftion there is no occa- 
fion to fee the threads* 
The following is the conftrudtion of this Iconanti- 
diptic Telefcope, which 1 have already made ufe of, and 
which appears to be proper for obfervations made in the 
plane of the Meridian. 
That the folution may be applicable to Telefcopes,it is 
proper that ad = az, aB=az. 
Then put ad=f the focal diftance of the lens a, 
<2b =/ the focal diftance of the lens a x 
a a=f-/, 
a e -ax-av , = f - 2 f y 
BC 
conflrutSfion on n’a pas befoin de voirles fils. 
Voiei la conftru£tion de cette lunette Iconantidyptique dontje me fuis deja- 
fervie et qui me paroit commode pour les obfervation faites dans le plan du. 
Merldien. 
Pour que. la folution foit aufli appliquable aux oculaires il convient que. 
AEzaz, fisraz. 
Alors on fera ad = f foyer de la lentille a s 
aB—f foyer de la lentille a 7 
<7A = F-/, 
AB ~ a A — «BZF- 2/5 
fSf 
5 
