1923 Roadster

My 1923 Roadster.

No picture?

Can anyone give me some insight on the oil reservoir that is mounted next to the horn on the firewall? The copper line drops down and trees off. One line goes to the front of the motor and the other goes to the transmission housing. My father restored this 1923 model t roadster, and I inherited it. Is this somehow for the transfer of oil from back to front? Not sure. The black can with the lid screwed onto it.