A De La Rive apparatus is a specialized gas discharge device designed to demonstrate that the glow discharge in a low pressure environment can be influenced by electromagnetic fields. The De La Rive apparatus consists of two parts, a low vacuum electron tube with a tubular depression passing through it's radius, and an electromagnet that mates to the tube such that the electromagnet's core passes through the center of the tube. When the tube is activated and a voltage is passed across the electromagnet, the discharge beam will rotate around the ring-shaped anode in the same direction as the magnetic field, demonstrating that the glow discharge is made up of charged particles that can be influenced by an external electromagnetic force.
This example, manufactured by Electro Technic Products, was probably produced sometime in the mid 20th century as an educational demonstration for high school and college physics classes. Interestingly, the control coil for this example is made out of the re-purposed shell of an Electro Technic BD10 violet ray generator, a device commonly used as a sex toy amongst more adventurous members of the human population.
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