Re: Hull Teslathon

Ed Harris wrote as part of a message...
> ps I got to see Hull's inverted Magnifier for the first time in person! 
> I was 5ft beyond the 120 inch strike range and could feel puffs of wind as 
> the arcs reached toward me! Also, the free coil was uncoated and showed 
> no signs of corona "haze" at either end....
Can you please explain the term "inverted" ?