Bidspirit auction | Crookes Radiometer w/ Cathode Ray

Crookes Radiometer w/ Cathode Ray - This fascinating piece of vintage scientific apparatus is a Crookes Radiometer variant combined with a Cathode Ray / Crookes Tube demonstration element, dating from the late 19th to the very early 20th century (circa 1890s–1910s). Designed as a physics laboratory demonstration piece to illustrate the kinetic theory of gases, the behavior of radiant energy, and early vacuum tube electronics, it represents a sophisticated era of educational scientific instrumentation. The glass body features a distinct profile that tapers into two protruding side arms. These arms terminate in delicate wire loops (electrodes) intended for connection to a high-voltage power source, such as a Ruhmkorff induction coil. This setup allowed instructors to pass an electrical current through the rarefied gas within, creating a luminous discharge. Internally, the device features a complex, two-tiered mechanical setup. A central glass spindle supports an upper horizontal metal disk shield and a lower set of four lightweight vanes, typically made of mica or aluminum. One side of each vane is polished, while the opposite side is coated in matte black lampblack. When exposed to radiant energy, the temperature differential on the vane surfaces causes residual gas molecules to bounce off the darker sides with more kinetic energy, spinning the mill. Simultaneously, the upper disk acts as a target or deflecting shield to demonstrate how cathode rays (electrons) travel in straight lines or interact with mechanical elements inside a vacuum. For an object of this age and extreme fragility, its condition is exceptional. The hand-blown glass stem remains intact and inserts cleanly into the turned-wooden base. The glass envelope is entirely free of cracks, chips, or other detrimental features, preserving a remarkably pristine example of historical scientific glassblowing. Technical Dimensions: Overall Height: 18 inches. Glass Apparatus Height: 16 inches. Maximum Width (Side Arms): 7.5 inches. Lower Bulb Diameter: Approximately 4.5 inches. Please see photos for condition. Note: Pickup/Transport required. Contacts available Post-Auction. From the Dale Beeks collection.