Okay -- I just went through all the Volume 15s (1965) that we have (Numbers 1, 2, 3, 6 -- missing 4 & 5) and couldn't find any such letter. I went back through each issue to make sure it wasn't someplace other than in "Correspondence." So I guess that narrows it down to Vol. 15, Nos. 4 or 5, eh?

Linn