Engineer and inventor; his discoveries, especially the vacuum tube, made possible the amplification of radio signals. Commonly referred to as The Father of Radio. In 1910, de Forest staged the first musical broadcast in history of an Enrico Caruso performance for the Met. TLS, one page, 8 x 10.75, Lee de Forest Laboratories letterhead with a metallic red, silver and blue sticker which reads 'We will exhibit June 13-17, 1938 San Francisco,' June 7, 1938. A letter to Dr. Moses Eisenberg with good technical content relating to a question regarding the ohmic resistance of the mandibular and maxillary bone structures. In part: 'Unfortunately, we are unable to find any definite data regarding the actual ohmic resistance of such live structures; the resistance of the dried bones and in cadavers is much too high to be of any value for your purpose...We regret our inability to give you anything more definite on this subject.' In fine condition with a trimmed left edge, some wrinkling; the page has been affixed to and smoothed on sturdier paper. RRAuction COA.
