A Cat-clock.

The following curious incident is to be found in Huc's "Chinese Empire":

"One day, when we went to pay a visit to some families of Chinese
Christian peasants, we met, near a farm, a young lad, who was
taking a buffalo to graze along our path. We asked him carelessly
as we passed whether it was yet noon. The child raised his head
to look at the sun, but it was hidden behind thick clouds, and he
could read no answer there. 'The sky is so cloudy,' said he; 'but
wait a moment;' and with these words he ran towards the farm, and
came back a few minutes afterwards with a cat in his arms. 'Look
here,' said he, 'it is not noon yet;' and he showed us the cat's
eyes by pushing up the lids with his hands. We looked at the
child with surprise; but he was evidently in earnest, and the
cat, though astonished, and not much pleased at the experiment
made on her eyes, behaved with most exemplary complaisance. 'Very
well,' said we, 'thank you;' and he then let go the cat, who made
her escape pretty quickly, and we continued our route. To say the
truth, we had not at all understood the proceeding, but did not
wish to question the little pagan, lest he should find out that
we were Europeans by our ignorance. As soon as we reached the
farm, however, we made haste to ask our Christians whether they
could tell the clock by looking into the cat's eyes. They seemed
surprised at the question, but as there was no danger in
confessing to them our ignorance of the properties of the cat's
eyes, we related what had just taken place. That was all that was
necessary; our complaisant neophytes immediately gave chase to
all the cats in the neighbourhood. They brought us three or four,
and explained in what manner they might be made use of for
watches. They pointed out that the pupils of their eyes went on
constantly growing narrower until twelve o'clock, when they
became like a fine line, as thin as a hair, drawn perpendicularly
across the eye, and that after twelve the dilatation
recommenced."

Fonte: Cats