The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com (C) Jeff Behary 2010 jeff_behary@hotmail.com  Swett & Lewis High Frequency "Alternating" X-Ray Tube Some curious images of a rare Swett & Lewis High Frequency X-Ray Tube, ca. 1901. Normally this tube would be a concept from an old manual.  In this case, only a couple of manuals still exist.  (literally). The same applies to the rare apparatus.  Here is the beginning of a novel X-Ray apparatus  that Kinraide patented in 1904.   This became the basis of the commercial "Jackson High Frequency Coil"...  Not sure if this bipolar conical coil version ever went into production.  This is how the recreation of apparatus on this website begins:  In this case, a patent drawing - which is only that:  a drawing. The rest involves hours of CAD work and calculations, both mechanical and electrical to come up with what would be an accurate reproduction of the original. This X-Ray tube looks simple, but required a great deal of CAD work to make successful!  In this case, it required drawing a typically hand-blown glass vacuum tube. Cross-section of hollow glass vacuum tube. ...and while the CAD drawings are useful for artwork down the road... The real answers lie ahead with the data learned when the switch is eventually thrown! Updated:  01 June 10 (C) Jeff Behary, 2010