Three principles (in Chemistry), b. [261].
Toletan tables, a. [177].
Transition rocks, b. [530].
Transverse vibrations, b. [44], [93], [101].
Travertin, b. [546].
Trepidation of the fixed stars, a. [179].
Trigonometry, a. [167].
Trivial names, b. [392].
Trivium, a. [199].
Tropics, a. [131].