Thanks for the replies. On further research, it turns out that the author was the chief technician at Aegler Rolex in the 1920s and 1930s, and is credited with inventing the modern perpetual rotor. Here's a little interesting history behind the man:
Harry Borer, whose family owned the movement manufacturing facility known as Rolex Bienne/Biel, has passed away at the age of 89, his family announced on June 15. Borer was director of the Bienne facility from 1967 to 2001. The Borer family, and prior to them the Aegler family, had through the factory in Bienne been the primary supplier of movements to Rolex Geneva since 1905. Until the 2004 deal that resulted in the Borer family selling Rolex Bienne to Rolex Geneva, Bienne had been a separate company albeit with a long history between the two firms. ADVERTISEMENT
In 1905 the firm was not yet called Rolex Bienne; it was then known, after the family name of its owners, as Aegler S.A. and in 1920, Hermann Aegler became a Rolex board member after purchasing a large block of Rolex stock. Aegler's nephew Emile Borer became technical director in the mid-1920s, and as the commercial ties between the two firms became closer and closer, the decision was made by the Aegler/Borer family to rename the factory Manufacture des Montres Rolex SA, with an agreement that Rolex would purchase movements only from Bienne, and Bienne would only sell movements to Rolex. This arrangement continued without interruption and almost without exception (a notable one being the use by Rolex of modified Zenith El Primero movements, starting with the Daytona ref. 16520) until 2004.
