The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com 330 Turn Pancake Coil For Producing Phantom Streamers: Ball Terminal Negatively Charged Baking Coil in oven... Finished Coil.  Secondary Coil is approx. 4.5" OD.  Primary & Secondary Coils are embedded in wax, 9" diameter x 2.25" Thick. The centre post is 2" OD with a 3/4" Brass Ball. Sparks are strong and static-like Spark length changes little when a 6" sphere replaces the .75" sphere.  Sparks do become thicker and louder. Appearance of Phantom Streams in dark.  Only the white sparks can be seen if the room isn't completely dark. Unusual things about the compact multi-layered coils operated from low voltage: Phantoms take the shape of thick positive streams, rather than just straight thin lines. (In some cases the streams appear as thick as 1/4" or 1/2") In this coil, a small section of a brighter negative discharge can be seen just surrounding the ball. This stream is brighter and of a diffused shape, like miniature plumes.    I look forward to the day I can reproduce the plumes the way Kinraide did!  Until then though, I am really happy to be able to do this.  The discharges are highly intriguing!! A smaller version has been made also. Simplistic version of Ralph C. Browne's patent (1904) This coil is wound flat at the periphery and gradually becomes multi-layered toward the centre. Ralph Browne was one of Kinraide's first competitors for Pancake Coils.  His work later turned up in the Tesla Coil section of the Knott Apparatus catalogues.