Viscosimeter

Hard to find, the viscosimeter was used to determine the petrol dilution of the motor oil.
In the cold regions, the oil was diluted with petrol to prevent the motor from freezing. Adding too much petrol was dangerous then this tool was very useful.

This Air Bubble Viscometer, helped to determine how high the petrol dilution of the motor oil was. The three right-hand glass tubes were filled with various kinds of petrol-diluted oils.
The left tube was filled with the oil from engine to be tested (with the same quantity as the other three).
By turning upside down and looking how quickly the air bubble rise compared to the other tubes, it was possible to determine the dilution.

• Tube #1 had the oil mixed with 25% gasoline
• Tube #2 was diluted to 15%
• Tube #3 was undiluted