Conductor Of Light

Riddle: My first is a part of the day, My last a conductor of light, My whole to take measure of time, Is useful by day and by night. What am I?

Answer: An Hour-glass.

Source: https://www.riddles.com/524

Riddle: My first is a part of the day,
My last a conductor of light,
My whole to take measure of time,
Is useful by day and by night.
What am I? Answer: An Hour-glass. — by Anonymous v1.

Riddle: My first is a part of the day,
My last a conductor of light,
My whole to take measure of time,
Is useful by day and by night.
What am I? Answer: An Hour-glass. — by Anonymous v2.