I don't know if it's the first mention in print, but Archibald Sharp devotes several paragraphs (and a drawing) to the oval chainring in his 1896 opus "Bicycles and Tricycles". He just says it "has been used", didn't say by whom, but it wasn't his invention.

"B&T" also shows a drawing of a bike with aero disk wheels, the front being a 4-spoke to reduce the effect on steering from side winds. Almost 130 years ago.