Helicopter : (double rotor) Heinrich Focke, Germany, 1936; (single rotor) Igor Silorsky, U.S.A., 1939.
Helium First Observed on Sun: Sir Joseph Lockyer, England, 1868.
Home Videotape Systems (VCR) : (Betamax) Sony, Japan, (1975); (VHS) Matsushita, Japan, 1975.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment