Therefore it is probable that the air coming upon the superficies of the oil keepeth it fresh and new.

And this is the reason that the top of wine is worst, and of oil best; because age betters the one, and spoils the other.
QUESTION IV.

WHAT WAS, THE REASON OF THAT CUSTOM OF THE ANCIENT ROMANS TO REMOVE THE TABLE BEFORE ALL THE MEAT WAS EATEN, AND NOT TO PUT OUT THE LAMP?
FLORUS, EUSTROPHUS, CAESERNIUS, LUCIUS.
Florus, who observed the ancient manners, would not let the table be removed quite empty, but always left some meat upon it; declaring likewise that his father and grandfather were not only curious in this matter, but would never suffer the lamp after supper to be put out,--a thing about which the ancient Romans were very careful,--while those of to-day put it out immediately after supper, that they may lose no oil.
Eustrophus the Athenian being present said: What could they get by that, unless they knew the cunning trick of our Polycharmus, who, after long deliberation how to find out a way to prevent the servants' stealing of the oil, at last with a great deal of difficulty happened upon this: As soon as you have put out the lamp, fill it up, and the next morning look carefully whether it remains full.

Then Florus with a smile replied: Well, since we are agreed about that, let us inquire for what reason the ancients were so careful about their tables and their lamps.
First, about the lamps.

And his son-in-law Caesernius was of opinion that the ancients abominated all extinction of fire, because of the relation that it had to the sacred and eternal flame.