Abstract: A floor treating machine of the single rotary brush type having a handle and a motor both laterally offset from the axis of rotation of the brush in a direction to impart a tilting couple opposed to that arising from operator forces counteracting the reaction couple on the handle.

Abstract: The disclosure relates particularly to audiometers, such as used in ascertaining the hearing ability of test subjects. Functionally, the new audiometer is similar to the so-called von Bekesy audiometer. However, the new system incorporates unique and advantageous circuit arrangements which enable controlled variable attenuation of a power signal to be achieved through simple and reliable electronic means. The new system eliminates the costly and fast-wearing electro-mechanical mechanism customarily used and heretofore considered necessary in a von Bekesy audiometer. The new electronic attenuation system includes means, effective in the extremely low power range of audiometer signal generation, to apply a high level, controllably variable signal, and to attenuate that signal across a high ratio voltage divider.