Complex sentence: On the northern side of the passage there is still an iron bar-this is the Calibration Shoe of Speyer (Speyerer Werkschuh), an obliging calibration for each merchant of the city.
Split into simpler sentences: On the northern side of the passage there is still an iron bar. This is the Calibration Shoe of Speyer (Speyerer Werkschuh), an obliging calibration for each merchant of the city.