( 374) 
above the Horizon. For, if the Obfervation of the Diameters be 
exadl^ as in thefe Situations the Moon changes not confider ably 
^herDiftance from the Earth in-^. ory. hours , th^ Difference of 
- the Diameters will ftiew the Proportion there is of her Diftance, 
with the Semi-diameter of the Earth. I do not enlarge ^ becaufe 
.that as foon as one hath this Idea , the reft is eafie. The fame 
would yet be pradiis'd better in the places, where the Moon pafses 
through the Zenith , than here for the greater the difference is 
of the Heights , the greater is that of the Diameters. I do not 
note (for itealily appear^s) that, if one were under thefameii/^r/- 
^iUn^onhQ (an\Q Azimuth in two very diftant places , and took a-t 
the fame time the Diameter of the Moon y one would do the 
/ame thing though this Method goes not to precifenefs. 
Fromwhat has been faid, may be coUeded thereafon of the 
'Obfervation , vvhich M. Heveliu^ made in the lail Ecliffeof the 
Sun^ touching the increafe of the Moon's Diameter about the 
end. I am exceeeding glad , that a perfon ^ who probably knew 
. Eot the caufe of it 3 has made the Experiment-* but itisftrange," 
chat until now no Aftronomer has forefeen , that that (hould hap- 
pen , nor given any precepts for the Change of the Moons Diame- 
ter in the Bcliffes of the Sun , according to the places, where they 
Ihould happen , and according to the Hour and Height , the 
Moon fliould have. For, what hapned in that Bcliffe of Augmen- 
tation , would have falii o ut contrarily, if it had been in the Even- 
ing-, for 5 the Moon , which in that Eclipfe^ that began in the 
Morning , was higher about the end than at the beginning , was 
nearer us , and confequently was to appear bigger ; But if the 
Ecliffe fhouldiiappen in the Evening, flie would be lower at the 
€nd, and therefore more diftant from us, .and confequently ap- 
pear lefTer. So alfo in two different places , wheieof one fhould 
have theEclipfe in the Morning, and the other at Noon, the 
Moon fliould appear bigger to him that hath it at Noon: 
And (lie mull likewife appear bigger tt) thofe , who fliall have a 
U^QX Elevation of the Pole under the fame Meridian^ becaufe the 
Moon will be nearer them. 
. V I wifh , I could fatisfie you abou t the Of tick Glaffes of Signior 
Burattini m Poland y which he hath fent hither 5 but I have not 
yecfeen their performances my felf. I only faw oucc the GlafTes, 
which 
