Aircraft inclinometer. Used to indicate the pitch of an aircraft.
The horizonal part for roll is missing.
Same kind as used on the "Spirit of St. Louis"...
Made by: W.C. Rieker P-8266 s/n 199
Made in the early 1920s
Rieker Inc has been manufacturing slip indicators for the aircraft industry since the early 1920's. One of the most famous installations seen in 1920's, was the use of a pair of Rieker glass tube instruments on the panel of the Ryan NYP "The Spirit of St. Louis". In 1927 Charles Lindbergh chose the lightweight Rieker P-1057 Degree Inclinometer to give him climb and descent angle information.