( 4*5 ) 
different in every differing Horizon ; exactly after the 
fame manner as the Rainbow feen in the lame Cloud is 
not the fame Bow, but different to every feveral Eye. 
Nor is it to be doubted, but the Pyramidical Figure 
of thefe Afcending Beams is Opticall y fince according to 
all likelyhood they are parallel* Tided, or rather taporing 
the otherway. But by the Rules of Perfpe&ive, their 
Sides ought ro converge to a Point, as we fee in Pidures 
the Parallel Borders of ftreight Walks, and all other 
Lines parallel to the Axis of Vifion, meet as in a Center. 
Wherefore thofe Rays which arofe highed above the 
Earth and were neared the Eye, feemed to terminate in 
Cufps fufficiently acute, and have been for that rcafon 
fuppofed by the Vulgar to reprefent Spear s, Others feen 
from afar, and perhaps not riling fo high as the former, 
would terminate as if cut off with Plains parallel to the 
Horizon, like truncate Cone c or Cylinders : thefe have 
been taken to look like the Battlements and Lowers ora ; 
the Walls of Cities fortified after the ancient manner, 
Whilft others yet further off, by rea'on of their great 
Didance, good part of them being intercepted by the In- 
terpofition of the Convexity of the Earth, would only 
fhew their pointed Tops, and becaufe o* their Shortneis 
have gotten the Name of Swords* 
Next the Motion of thefe Beams, furnifhes us with a 
new and, as it Teems to me, mod evident Argument to 
prove the diurnal Rotation of the Earth : (though that 
be a matter which, at preient, is generally taken by the 
Learned to be pad difpute) For thofe Beams which role 
up to a Point, and did not prefently difappear, but con- 
tinued for fome time, had mod of them a fenfible Motion 
from Ead to Weft, contrary ro that of the Heavens; the 
biggeft and tailed of them, as being neared, fwifted ? 
and the more remote and ihorter, flower. By which 
means, the one overtaking the other, they would fome- 
Uub, 'timss. . 
