Subject: Speed of an electron in a current.

I am currently majoring in electronics engineering technology. I have been told 
that the electrons of a circuit travel at the same velocity as the electrons of 
another circuit regardless of voltage or current, assuming the two circuits are 
of the same material. My question is, how was this first determined. It is 
difficult for me to imagine that electrons in a circuit will fail to increase in 
speed with an increase in current.

Re: Speed of an electron in a current.