r i2 4 ] 
for magnifying ob]e£ts in optical experiments, till the 
beginning of the thirteenth century : but, upon re- 
viewing his dififertation, I find he finks the antiquity 
of that ufage a century lower than this. That learned 
writer adds further, “ That with regard to this que- 
" fiion, whether the antients made their aftronomi- 
“ cal obfervations without telelcopes, the affirmative 
“ is looked upon as certain ; becaufe, if this inven- 
“ tion had ever been known before, there is all 
“ imaginable reafon to believe, that the utility, 
“ which would refult from it, not only in aftro- 
“ nomy, but for feveral other purpofes, would have 
“ prevented its being afterwards loft.” Monf. Re- 
naudot declines entering into this con trover fy y but 
obferves, that Mabillon mentions a manufcript he 
faw in an abbey in the diocefe of Freifingen, wherein 
Ptolemy was reprefented obferving the ftars with a 
* tube, like our modern perfpedtive-glafies. This> 
manufcript is faid to have been written in the be- 
ginning of the thirteenth century j which date (fays 
Monf. Renaudot) is the more remarkable, becaufe 
plain fpedacles, which ffiould feem likely, in the 
nature of things, to have been invented firft, do not 
appear to have been known till a hundred years after; 
Then, having produced the evidences, which prove, 
that this latter difcovery was made about the time 
above-mentioned, he concludes with faying, “ that 
* Mabillon does not mention, that the tube had glafles ; neither 
indeed was that circumftance eafily difcoverable. Perhaps fuch 
tubes were then ufed only to preferve and diredt the fight, or to 
render it more diftindt, by Tingling out the particular objedt looked 
at, and (hutting out all the rays refledted from others, whofe pro- 
ximity might have rendered the image lefis precife. 
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