Surprisingly, LENOIR’s barometer/weather station (Lenoir 18), which was actually commercialised, is not mentioned in LENOIR’s numerous biographies.
On the other hand LENOIR’s design of an inflammateur (spark plug) for combustion engines in 1887, - somewhat hidden as the17th certificat d’addition attached to the main patent of 1883 (Lenoir 35) - deserves a special mention.
LENOIR’s « inventive activity » over the years is illustrated by the following graph which shows the
Number of patents and patents of addition filed per calendar year
The creative peaks coincide with the development of the two LENOIR engines: the gas engine starting in 1860 and the four-stroke engine starting in 1883.
LENOIR kept imagining and creating new objects and processes until almost the end of his life. In 1892, at the age of 70 and after leaving the centre of Paris for nearby La Varenne-Saint Hilaire, he kept filing patent applications on inventions made in a variety of technical fields.
LENOIR’s French patent portfolio also reveals that, on four occasions, he was registered as co-inventor of Pierre-Désiré PRUD’HOMME, fabricant d'appareils électriques and, on one occasion, as co-inventor of André-Etienne POSTEL-VINAY, fabricant d'appareils télégraphiques.