+------------------------------------------------------------------+ | | | Transcriber's note: The following printer errors have been | | corrected: | | Diaphasic changed to Diphasic (fig. 26 caption) | | Dash added (section on Continuous Transformation) | | Blurr changed to blur (after fig. 111) | | In creased changed to increased (after fig. 114) | | | | The inconsistent hyphenation of "break-down", "electro-motive" | | and "vibration-head" is as in the original. | | | +------------------------------------------------------------------+