Vintage Cars: positive ground electrical systems, engineer buddy, positive earth

Question
Me and some of my electrical engineer buddy were kicking around a question that we can not find the answer to. Why did some auto manufacturers use positive ground electrical systems. I think Ford did it in the 40's and MG did it for many, many years. Any ideas? Thanks.
Thanks,

Rich
Bethlehem, PA

Answer
Hi Rich,

My understanding is that positive ground, or "positive earth" as the British called it, was based on the unsubstantiated theory that somehow electricity flowed better in that direction. But as for the reasoning why anyone thought this was so, I can't say as I ever heard anything plausible about it. I'm sure somewhere is a detailed explanation, one that is no doubt scientifically unsound but convincing nonetheless.

best

Joe Troise