Meteorology   

archonship of Asteius. On the first day it set before the sun and

was then not seen. On the next day it was seen, being ever so little

behind the sun and immediately setting. But its light extended over

a third part of the sky like a leap, so that people called it a

'path'. This comet receded as far as Orion's belt and there dissolved.

Democritus however, insists upon the truth of his view and affirms

that certain stars have been seen when comets dissolve. But on his

theory this ought not to occur occasionally but always. Besides, the

Egyptians affirm that conjunctions of the planets with one another,

and with the fixed stars, take place, and we have ourselves observed

Jupiter coinciding with one of the stars in the Twins and hiding it,

and yet no comet was formed. Further, we can also give a rational

proof of our point. It is true that some stars seem to be bigger

than others, yet each one by itself looks indivisible. Consequently,

just as, if they really had been indivisible, their conjunction

could not have created any greater magnitude, so now that they are not

in fact indivisible but look as if they were, their conjunction will

not make them look any bigger.

Enough has been said, without further argument, to show that the

causes brought forward to explain comets are false.



7



We consider a satisfactory explanation of phenomena inaccessible

to observation to have been given when our account of them is free

from impossibilities. The observations before us suggest the following

account of the phenomena we are now considering. We know that the

dry and warm exhalation is the outermost part of the terrestrial world

which falls below the circular motion. It, and a great part of the air

that is continuous with it below, is carried round the earth by the

motion of the circular revolution. In the course of this motion it

often ignites wherever it may happen to be of the right consistency,