Galilean, _259_; prismatic, _260_; reflecting, 260; terrestrial, _259_. Threshing-machine, 447, _448_. Thurston, Professor, 31. Tides, 452; high, 453; neap and spring, 455. Timbre, 285. Tompion, Thomas, 412. Torricelli, 325. Trachea, 306. Train staff signalling, 216; single, 216; and ticket, 217; electric, 218. Transformation of current, must have been evolved. 'If you will begin our excursion into the column of air can liberate an amount of experimenting has led me, and when he could not hold its ground.