The ‘Planox Stéréo­scope Mag­né­tique’ was one of the most pop­u­lar French stereo view­ers and is notable for its inno­v­a­tive mag­net­ic mech­a­nism. The basic idea was devel­oped by Mod­este Noel, who reg­is­tered his patents in 1913 and 1914. Alexan­dre Plocq was like­ly the first to use Noel’s inven­tion for pro­duc­tion mod­els. The draw­ings of a third patent in 1920, again by Noel, show the sim­pli­fied mech­a­nism found in the view­ers that were actu­al­ly produced.
Lat­er ver­sions made use of bake­lite trays instead of wood­en trays. Due to the design of the bake­lite trays, it was always pos­si­ble to insert both 45x107mm and 6x13cm slides into the same mechanism.
The illus­trat­ed view­er is a much rar­er ear­ly ver­sion, whose mech­a­nism is only suit­able for the small­er 45x107mm wood­en trays, while 6x13cm Planox stere­o­scopes where much more com­mon for ear­ly versions.