The original Fusor.

[Drakkith]

I see on Wikipedia that the original fusor was abandoned and further versions had grids instead. Why is this? Were there any other disadvantages to the original fusor other than problems being scaled up?

[Dan Tibbets]

Assuming you are referring to this link:

http://en.wikipedia.org/wiki/Fusor

The first picture looks like it might have been the vacuum shell for the Hirsch Fusor. It was a complicated derivative of the original fusor and used ion guns with precision and complicated grids. The guts are not shown. If you want a picture of what was (near?) the first fusor, look for a picture of Farnsworth looking at a small apparatus mounted in a glass bell jar.
(Top right of the home page here)

Dan Tibbets

[Drakkith]

Thanks Dan!