CiS7o] 
cultation of Jupiter by the Moon, (a cafe that feldom 
happens) Jun. s- 
^ And thence to Sept. 26. (the fatal day when his ob- 
fervatories with all their furniture were deftroyed) which 
concludes the obfervations of that year. 
After thefe obfervations, of the year 1679 > ^7 
I^etters which had paflTed between the Author and di- 
vers other learned men, relating to the controverfy 
between him and Mr, Ht)ok^, about the ufe of Telefco^ 
pick^ Sights. 
The Firft, Third, and Fifth, are from Mr. Henry 
Oldenburg, Secretary to the 'Royal Society 5 and contain 
( belide fome other things , declaring the Society s 
great refped for the Author,) Mr. //(?^;^'^defcription 
ot his Tel efcopicJ^ Sights , with his reafons urging the 
ufe of them, AiBrm'ing that, for any Celeflial observa- 
tions, an Inftrument, with thefe, though but oj the Radius 
af one Span, may be^ made more exaU, than, with com» 
mon Sights , th^ befi that can he made , though of three^ 
/core jfoot Radius. That, whereas the na\ed Ey can hard- 
ly diftinguijb an angle of a Minute, it may thus di(iinguijb 
The Second, Fourth, Sixth, and Seventh, are the 
Authors anfwers to thole maintaining the contrary. 
Not thinking it poffible, that fo fmall an Inftrument 
can do fuch great things and that, with his own, he 
• can diftinguifh a much fmaller angle than Mr. Hoo\ 
will allow. Appealing to experience (which is to be 
the judge in this cafe;) and defiring (for inftance) Mn 
Hoo}(s Obfervations, (by his Inftrument) of Eight di- 
ftances propofed 5 to be compared with his own Obfer- 
vations of the fame ^ that it may be thence judged, 
whether are the moreexacft. (But could not obtain any 
one. ) And he believes that thofe who thus commend 
thefe, if they had ever made trial of liich large In^ 
ftrumentsj 
