July 8, 1960

Dr. Warner Gilson
Gilson Medical Electronics
Middleton, Wisconsin

Dear Warner:

| was happy to receive the 254 interference filter last month.
it does peak very close to where |! would want and it may be quite
useful for our purposes. One could wish that it did have a higher
transmission but that's that. {§ believe that we have arranged for
payment for this item. I'm not so sure that we have paid you for
the G4 Th lamp and ballast and will be happy to do so on your
invoice,

The G4 Th is not quite as clean in 2537 output as | might have
hoped. The main difficulty from my point of view Is that Its output
Is spread over a rather large area, and | am only able to use a
very small fraction of it.

For your own application you might find ft worthwhile to took
at the General Electric G4 SII lamp, the so-called ozone producing
lamp. This is an inexpensive, readily available lamp which requires
only a cheap resistance for ballasting and, like myself, you may find
its compactness useful. According to its specifications it should

ae be an even more concentrated source of 2537 radiation than the
Gh T4,

With best wishes,

Yours sincerely,

Joshua Lederberg