Timelighting / lighting

As time passes a candle’s flame shrinks. I propose a system which functions similarly to that of a candle light. As time passes the light will grow dimmer and shorter.
User Scenario
1.Pull up the glass top of the timelight.
2.The Timelighting turns on.
3.Wind a spring to set the length of time the light will remain on. The more you wind the spring the longer the light will stay on.
4. Enjoy your time reading a book or working. While performing your action you will notice the light grow dimmer. You can tell how much time has passed by the strength of the light.
5. The Time-lighting will turn off automatically when the time ends