I recently met a friend named Jerry (or Gerry) Cohn who was known many
years ago as Jerry (or Gerry) The Magician.  Ho told me he appeared on
the Tonight Show with Johnny Carson in the erarly days of the show. 
Did he appear and (assuming he did), where can I find information
about that show?

Lehdan --

There's only one Gerry (Gerry Cooney, the boxer) but lots of Jerry's
from 1969 onwards.  You can search them here:
"The Official Tonight Show Website"
http://media.johnnycarson.com/carson/search/index.jsp

I tried a search through 1980 using the New York Times and can't pin
down your guy but this may help.

It's also important to remember that Johnny Carson had a variety show
even before the Tonight Show.

Best regards,

Omnivorous-GA

A reference to "Jerry the Magician" and Bob Hope (no Carson):

"Bob introduced "Jerry The Magician" who prepared to perform his fake
guillotine trick on Bob.
Jerry said, "If this trick doesn't work out, we will donate the brains
to the Chief Master at Arms"
http://www.angelfire.com/de/classicalstories/page3.html