Thomas Burton Kinraide was the one of the first people to take the concepts of Nikola Tesla and create marketable apparatus from them.  He pioneered the first practical portable high frequency X-Ray machine ("The Kinraide Coil") shortly after Röntgen's discovery in 1896.  The initial apparatus were made in his Spring Park Laboratory in Jamaica Plain, MA. 

One of the earliest visitors to this laboratory was fellow electrotherapeutic pioneer and physician Frederick Finch Strong.  It was through Strong's 1907 book "High Frequency Currents" that I became fascinated with Kinraide and his work. 

Once in Kinraide's laboratory, Strong witnessed the most power X-Rays of that time period.  Kinraide and Tesla were independently the first people to create X-Rays powerful enough to penetrate the entire body, as opposed to just the hands or limbs.

This was Strong's first experience with Tesla Coils.  He would go on to pioneer the first therapeutic Tesla Coil (with the help of Earle Ovington, a man who later made world-fame as the first US Airmail pilot) and the famous glass vacuum electrodes to apply the new "high frequency" currents.

While researching Kinraide's patents, it is interesting to note that he the first applicant of several classes of electrical patents.  In other words, it isn't unusual to find a class of 60,000+ with the first one being that of Kinraide!

The Spark Gap in his early Kinraide Coils were in the form of hollow copper plates that could be filled with water to allow cooling.  This was the earliest form of Quenched Gap, something later adopted for wireless telegraphy (made famous by  Lepel).  In developing this gap, he also created an automatic regulating system so that the distance of the plates could be adjusted automatically by the current consumption of the machine.  This concept was tested for various carbon arc lamp circuits, but this the first time it had been applied to spark gaps for high frequency apparatus. 

The "Kinraide Coils" were high frequency high potential induction coils wound in the form of flat concentric spirals.  These were a modified design of Tesla's original lecture coils, and one of the only Tesla Coils ever mass produced that operated in the lower frequency range as did Tesla's.  The transformer or self-induction coils used in these apparatus provided approximately 1,000V at 200 - 400mA to a large condenser that discharged slowly across the large plates and into the flat spirals.  In the early part of the century at the height of electrotherapeutics it was said by Strong and others that the Kinraide Coil was the most efficient Tesla apparatus ever placed on the market.  It also operated at the lowest frequency of any coil yet marketed.

Other original ideas of Kinraide were the use of a torroid or "limitless plane" as a top load capacity for his coils.  He further developed this concept into the point-plane method for rectifying Tesla Coils and high voltage alternating currents.  He further extended this concept into a combination point-plane discharger that could be reversed at will, making it possible to obtain both positive or negative effects from the same terminal.

Included in this archive are also several patents by Howard Jackson, an electrician who worked for Swett & Lewis.  Swett & Lewis were given the rights to manufacture Kinraide's inventions under his supervision.  Together they developed one of the most powerful apparatus for producing resonator "effluve" effects, The Jackson Coil.

A combination X-Ray/Electrotherapeutic machine called the "Cyclone Coil" was also developed by Kinraide, but it appears to be a modified combination of the two earlier machines of which no patents can be found at present.