Astronomy.

*93

Hqf '

0^? Cr ^ orr sted in circular , but very elliptic^ so in this Instrument, a peculiarr Con-

Mg -

^Qo n * S Ecjus! anc! similar to the dark Shadow of the

i 11 htz 1 1)ow fee how much of the Earth’s Surface)Sr 3t an 7 Time involved in the Moon’s dark Sha-psj e Quantity of the Arch EF. T J ~- *■"Aocin r' l! L sopposc the Sun to be an Ape

In order to

Apogee,

and the

. Oon j Lllc uuu tvj to- .... ^

o, ri g ee ; and in that Case the Height of thejptijft la <W will be about 6i Semidiameters, and

J, ‘ " ’ '' ’ ' ^ ?In p;„. >L.l

"±\XKJVJ Will UC dUUUl J i. -.

If^ nce of tbe Moon about 5 0 ; that is, (in Fig. 4-) PI. LX.^li> T" so, DT — g6, aud TE = i. In this Cafehe; e fsolf-Angle of the Shadow T K E — 15 5° »

As.^j § least of all. Therefore fay,

I s ta /A or the Side T E = i = o.

^ is o. Side TK = 5 =0.698970

^ llle of the Semi-angle TKE=i 5 / 50^ =7.663238

°f the Angle TEK= 1" 19' ip'' = 8.362208N f 0 T E K + T K E = A T E = A E = 1 0 35 >sor e ,* E = ,» Tn - ~ too" - 220 Miles Statute Mea-

%

. . ’VyV- T~ 3 ^ O .— I 9 D — _

lc *' 's therefore the Diameter of the dark

b 9- Earth’s Surface when greatest.

h " er;i 1,L “ Trr.ii find the Diameter of the

t ' ilu tt4, ter 3 Manner you

‘ a l Shadow at the Earth, as

S», Utnf-n . . —

GEFH, when

of U «auuw ac uic Miu.j c. --

5 3 t)i e s AH, that is, when the Earth is in Perihelia,,l°°» I' 1 her Apogee-, for then will the Sun’s» 9 n; - ' - - -,v-_ TJsi. the

T at rft 'aineter be equal to 16'jiHI) '■‘bi-angle of the Cone ; and thence we shall58 s Semidiameters of the Earth. In thisp f ^ r tae Distance of the Moon from the Earth isrk. P semidiameters * "" ^

fc.of*'

23 ^ ~ TIG, the

-Therefore, As T G = 1

I" of - - Sine of the Angle TIG= 16 ' 23 ";

3t Q + lV A o gIe 1 G N = 35° 42'. Sut I G N =Z and so ITG = IGN~TIG=.

^ooV^Houfcle of which is 70° 50' = G E F H

D l °. Siiic ^ nearly. /

e tp 0 |' lt . Ce an Eclipse of the Sun proceeds from an

° n of the Moon, ’tis evident, if the Sun andO 2 Moon