In article , ted
wrote:

In Alberta up until 1969 (when I left) There was an official whom we
called "Purple Charlie". He roamed the country checking every town and
village for purple gas. He'd start at one end of the street with a
large syringe with a rubber tube and check every gas tank. Farmers
were allowed to use "purple" in farm work vehicles but not their cars.
The fine was quite heavy. Farm gas was ordinary gas with purple dye
added and was less costly, hence the fine.

I remember purple gas on Grampa's farm north of Winnipeg when I was a
kid. We ran it in the snowmobiles, but not in the car.