( Slip ) 
this Obfervation I intend to write a fmall TraiSj when I 
(hall gain leifure 5 in which I lhall denaonftrate both the 
Diameter and Diftances of all the Planets by Obfervations; 
for which I am now pretty well fitted. 
Having obferv'd the Diftances and Pofitions of the 5 
Stars 3 by which ^ made his tranp^ I find, that Tyr/6(? errs 
5 minutes at leaft both in the Places and Latitudes of them 
compared one with another. And certainly he errs as much 
in many others ; fo that the labour of Mooficiur Hevelim to 
redify their places is very needful.Not that I find fault with 
TycbQ', 'tis a wonderj (confidering how difficult it is to fee 
plain Sights to a fmall Star) that ever he performed fo much 
and fo well: But if M- Hevelius de not Glaflls in their 
room J 1 fear,, we (hall but be where we were ^ and yet with- 
out this Reftitution we cannot exped any thing certain, 
much lefs accurate^ in Aftronomy» 
Lma 
