Schmalcalders Patent GB3545, 1812
Charles Augustus Schmalcalder (born Karl August Schmalkalder on 29th March 1781, in Stuttgart, Germany) came to England in the early 1800’s and was an inventor and optical instrument maker. He was responsible for introducing the use of a glass prism so the user can both sight the distant object and read the bearing on the compass card simultaneously. It had the added benefit of providing what are effectively transit sights on the compass.
This is a patent about the design and construction of the compass and it’s basic principles are still used today, over 200 years later. During the time Schmalcalder’s Patent was active, he sold compasses made by other instrument makers only. Instrument makers like the renowned Thomas Jones, who went on later to sell the same design from his own shop after the patent expired.
