240 
MicrocGRAPHuHia. 
is. Echpfed, for it alwayes pafles between the lines 1 2, and 
4 To which I fay, That if the Air befuch, asI have newly fhewn it to 
be, and confequently caufe fuchan inflection of the Rays that fall into 
it, thofedark Pexumbra's FYZQ, HX VT, andORP S, willall va- — 
nifh. For if we fuppofe the Air indefinitely extended, and to be no 
where bounded with a determinate refracting furface, as Thavethewn 
it uncapable of having, from the nature of it; it will follow, that the 
Moon will no where be totally ob{cured, but when it is below the A pex 
' Nj of the dark blunt Cone of the Earth’s fhadow:Now,from the fuppofi- 
tion, that the Sun is diftant about feven thoufand Diameters, the point 
_N, according to calculation, being not above twenty five terreftrial Se- 
midiameters from the Center of the Earth: It follows, that whenfoever 
the Moon eclipfed is totally darkned, without affording any kind of 
light, it muft be within twenty five Semidiameters of the Earth, and con- 
_ fequently much lower then any Aftronomers have hitherto put it. 
This will feem much more confonant to the reft of the fecundary Pla- 
nets 5 for the higheft of Fupiter’s Moons is between twenty and thirty 
Jovial Semidiameters diftant from the Center of Jupiter; andthe Moons . 
of Saturz much about the fame number of Saturnial Semidiameters from 
the Center of that Planet. 
» But thefe are but conjectures alo,and muft be determin’d by fuch kind 
of ObfervationsasI have newly mention’d. = 
Nor willit be difficult, by this Hypothefis, to falve all the appearances 
of Eclipfes of the Moon, for in this Hypothefis alfo, there will be,on each 
fide of the fhadow of the Earth, a Pezumbra, not causd by the Refratti- 
onof the Air, as in the Hypothefis of Kepler; but by the faint inlight- 
ning of it by the Sun : For if, inthe fixth Figure,we fuppofe ES Q.,, and 
G SR;to be the Rays that, terminate the ye at hen eitherfide of the | 
Earths ESQ coming from the upper limb of the Sun, andG SR. from 
the under it will. follow, that the fhadow of the ‘Earth, within thofe 
Rays, that is, the Cone GSE, willbetotally dark. But the Sun being 
nota point, but a large area of light, there willbe a fecondary dark 
Cone of fhadow EPG, which willbe caus’d by the earth's hindring 
part of the Rays of the Sun-trom falling on the parts G PR, and EP Q. 
of which halved thadow, or Penumbra, that part will: appear brighteft 
whichlyes neareft the terminating Rayes G P, and EP, and thofe dar- 
kerthat lye neareft to GS, and ES: whentherefore the Moon ap- 
, povaiytsc dark in the middle of the Eclipfe,fhe muft be below §,that is, 
Ww 
vy fs 
s - tray : 
and Py. pat 
‘ ee 
ere : - 
LS 2 ae 
ahh 
vech § and. Fs when fhe appears lighter near the middleof the 
Eclipfe; the muft pafs fome where between RQ:and $3 and when the 
is altke light through the whole Eclypfe, the muft pafs between RQ, 
