Scarce letter signed by inventor and entrepreneur Nikola Tesla, whose electric inventions helped light the early 20th century. Dated 4 March 1919 on his Tesla Company, Inc. stationery at 8 West 40th St. in New York, Tesla writes to Edwin Fulton Pottenger, an inventor of internal combustion engines. Tesla writes in part, ''...my turbines can operate at practically any pressure obtainable, the higher the better, and they carry easily 200% overloard [sic] without damage.

I am at work now on an outfit which will be particularly suitable for tractor purposes and also am perfecting my turbo-blower, making a small and compact unit...[signed] N. Tesla''. Single page measures 8'' x 10''. Folds with one slightly affecting ''N'' in signature, light wear, and three hole punches on left side, with reinforcement. Very good condition.