For years, the chassis of every car has been connected to the battery negative. Changing that would require a re-design of the whole car's wiring system, and probably a lot more copper as every electrical accessory would now need a negative wire.
When cars had chassis, the earth was usually positive; but so long as the dynamo and starter motor were polarized correctly, it didn't really matter. It was the advent of radios which changed the situation.
For years, the chassis of every car has been connected to the battery negative. Changing that would require a re-design of the whole car's wiring system, and probably a lot more copper as every electrical accessory would now need a negative wire.
When cars had chassis, the earth was usually positive; but so long as the dynamo and starter motor were polarized correctly, it didn't really matter. It was the advent of radios which changed the situation.
