* ,at .the rajs of light bent into the polar 
openings, are prevented from reaching- 
moon, so that the earth produces a 
shadow the same as it would do if the an 
dn7 n /K Verg r VVaS a real one ’ a?ld not pro¬ 
duced by refraction.* * 
f he lower side of the map is the south 
side of the opening,from whence it slopes 
up on either hand to the high side. 
t lose meridians marked within the les- 
* e 7 ?^ ed mrcle are interior meridians, 
am t ose without are the proper extenor 
ones, all those meridians that are not con- 
mue quite up to the ninetieth degree, 
aieto be imagined continuous. 
i he small cross on the upper side of 
ne arge dotted circle,represents the high 
M-le «l the real verge, and is supposed to 
tinn* ? r /,' ear " e A,aaK "' ,l( ' l “- The junc- 
hT™ , ' me| idians, an inch and a half 
below Uie cross, shows the high side of 
nineXTd^eT’ ^ C ° nSfitufes the 
tiefh'pau'neloni^'T ' ine , re P res =nt s thefif. 
the sixtieth para e ‘ and Z*, ““ l”* within - 
j» that, the ."evened e ’iehdelh ■ With - 
continuous like the seventieth* 6 -7 8ei 7 er » as 
the outer one hmvptro tle th; with relation to 
^continuous is as yet doubtfu? A fifth*" Wh ‘ Ch * 
allel was omitted, owing* to «T th . ,nner P ar “ 
tingit; but it mav be 7 d'fficulty of cut- 
scribed by dividers near the centre'nf^^ 33 if 
and about one and three fourtlJof an^ 
diameter, traversing the inner pLi r J ? ch 1,1 
ner meridians. It will renreo 7 S the ln ' 
latitude somewhat between thl * paraI,el ®f 
degree and the concave e, ,"""' 1 '"' 
viewing* this parallel from a nosftin Cye 
the centre of the opening wn M h, £ h 0vei ’ 
the verge apparently thrown bLk-^^ 17 See 
tion, and the innermost reXn= k by refrac " 
what like looking into7 ^7^°^ Some * 
glass: should not, however* the •7 ha { )ed wi «e 
an inner sphere nrevenf * tne ln terference of 
means of its verge being th*” ° f ‘ he view b y 
manner. As the raV. ofLhr ? ° llt ’ in 
.are parallel, or are\hesame Tne^ ofvision 
-• - . Sa [ ne > a person m the 
*essi^'*strata 0 of b m 9^ !- h ? SU f ossive vel 'S es > ofsuo, 
prisms, successive! ^\ ar , ia , spheres, operating like 
pass over ^ hend the rays ot light, until they 
concave / c al verge around to the surface of the 
