The little 8-pointed star at the top is the fuel guage. The centre of it is an actual window into the petrol tank. There's a little wheel that is meant to indicate the tank level. When you fill it right up the petrol actually shows through the glass. Luckily modern petrol pump nozzles shut off before the petrol spills out onto the hot engine directly below the filler neck.
Elf and safety wouldn't allow that sort of design today, or the rod operated brakes. In the event of an emergency stop the method is to brace both feet on the brake pedal and attempt to pull the steering wheel off its column. 
