On the nature of things (books 4 - 6)   

Might not alike be true- or aught there were
Wherefore thou mightest risk embracing one
More than the other notion. Then, again,
Why a new moon might not forevermore
Created be with fixed successions there
Of shapes and with configurations fixed,
And why each day that bright created moon
Might not miscarry and another be,
In its stead and place, engendered anew,
'Tis hard to show by reason, or by words
To prove absurd- since, lo, so many things
Can be create with fixed successions:
Spring-time and Venus come, and Venus' boy,
The winged harbinger, steps on before,
And hard on Zephyr's foot-prints Mother Flora,
Sprinkling the ways before them, filleth all
With colours and with odours excellent;
Whereafter follows arid Heat, and he
Companioned is by Ceres, dusty one,
And by the Etesian Breezes of the north
At rising of the dog-star of the year;
Then cometh Autumn on, and with him steps
Lord Bacchus, and then other Seasons too
And other Winds do follow- the high roar
Of great Volturnus, and the Southwind strong
With thunder-bolts. At last earth's Shortest-Day
Bears on to men the snows and brings again
The numbing cold. And Winter follows her,
His teeth with chills a-chatter. Therefore, 'tis
The less a marvel, if at fixed time
A moon is thus begotten and again
At fixed time destroyed, since things so many
Can come to being thus at fixed time.

Likewise, the sun's eclipses and the moon's
Far occultations rightly thou mayst deem
As due to several causes. For, indeed,
Why should the moon be able to shut out
Earth from the light of sun, and on the side
To earthward thrust her high head under sun,
Opposing dark orb to his glowing beams-
And yet, at same time, one suppose the effect
Could not result from some one other body
Which glides devoid of light forevermore?
Again, why could not sun, in weakened state,
At fixed time for-lose his fires, and then,
When he has passed on along the air
Beyond the regions, hostile to his flames,
That quench and kill his fires, why could not he
Renew his light? And why should earth in turn
Have power to rob the moon of light, and there,
Herself on high, keep the sun hid beneath,
Whilst the moon glideth in her monthly course
Athrough the rigid shadows of the cone?-
And yet, at same time, some one other body
Not have the power to under-pass the moon,
Or glide along above the orb of sun,
Breaking his rays and outspread light asunder?
And still, if moon herself refulgent be
With her own sheen, why could she not at times
In some one quarter of the mighty world
Grow weak and weary, whilst she passeth through
Regions unfriendly to the beams her own?