John, the ‘cooking pot’ on top of fuel tank is an oil bath air filter. Additional air filtering is provided by oil soaked wood shavings (the long thin ones used as packing material) in the inlet tube. These machines originate from Switzerland and are built to a very high standard. Geo Monro sold the earlier models and in 1948 started producing the model 56 under licence, they went on to produce the smaller model 35.
