Patent for a rotary steam-engine that provides "a new and useful machine of this character wherein a head or pressure of steam shall be utilized to its fullest extent with a consequent increase in power over other engines worked under the same head or pressure of steam. To this end the main and primary object of the present invention is to provide a simple, economical and durable steam engine of the rotary type having few working parts, but one which shall run easily and steadily and will develop considerable power" (lines 9-19).