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above the Horizon. For, if the Obfervation of the Diameters be 
exadD, as in thefe Situations the Moon changes not confider ably 
her Diftance from the Earth in 6. or 7. hours , the Difference of 
the Diameters will fhew the Proportion there is of her Diftance, 
with the Semi-diameter of the Earth. I do not enlarge, beeaufe 
that as foon as one hath this Idea , the reft is eafie. The fame 
would yet be practis’d better in the places, where the Moon pafses 
through the Zenith , than here *, for the gteater the difference is 
of the Heights, the greater is that of the Diameters. Ido not 
note (foriteafily appears) that, if one were -under the fame'^r/- 
dian^ or the fame Azimuth in two very diftant places , and took at 
the fame time the Diameter of the Moon , one would do the 
fame thing • though this Method goes not to precifenefs. 
From what has been faid , may be colledled- the reafon of the 
Obfervation , which hA.Hevelius made in the laft Eclipfe of the 
Sun , touching the increafe of the Moon's Diameter about the 
end. I am exceeeding glad , that a perfon , who probably knew 
not the caufe of it, has made the Experiment: but itisftrange, 
that until now 7 no Aftronomer has foi efeen , that that fhould hap- 
pen , nor given any precepts for the Change of the Mbons Diame- 
ter in the Eclipfes of the Sun , according to the places, where they 
fhould happen, and according to the Hour and Height, the 
Moon fhould have. For, what hapned in that Eclipfe of Augmen- 
tation , would have fain o ut contrarily, if it had been in the Even- 
ing ^ for , the Moon , which in tha t 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 
Eclipfe fhould happen in the Evening, flue would be lower at the 
end, and therefore more diftant fromuS, and confequently ap- 
pear leffer. Soalfo in two different places, wheieof one fhould 
have the Eclipfe in the Morning , and the other at Noon , the 
Moon fhould appear bigger to him that hath it at Noon: 
And fhe muft likewife appear bigger to thofe ; who fluall have a 
letter Elevation oh the Founder the fame Meridian , beeaufe the 
Moon will be nearer them. . 
Iwifh, I could fatisfie you about th e Optick Glaffes of Sigmor 
Burattini in Poland , which he hath fent hither 5 but I have not 
Vetfeen their performances myfeif. I only faw once the Glaffes, 
J which 
