Final answer:
The 'secrets' of the mason comprised the practical knowledge of geometry and arithmetic, along with experience-based rules necessary for construction. The physical tools used included the Masonic Square and Compass, Plumb Line and Level, among others.
Step-by-step explanation:
The 'secrets' of the mason refer to the knowledge and practices of master masons who directed the construction of medieval cathedrals and other buildings without the modern theoretical engineering knowledge we have today. Instead, they used empirical rules derived from experience. The tools they used to measure and manipulate their constructions included the Masonic Square and Compass, which are also prominent symbols of Freemasonry, representing both the trade's practices and ethical conduct.
The Plumb Line and Level were essential for ensuring vertical and horizontal alignment. A Trowel and Mortarboard were practical tools used in the application of mortar and the laying of bricks or stones. The Gavel and Apron are more symbolic, with the gavel representing the authority and discipline of the master mason and the apron symbolizing the protection and pride in one's work.