Seriously though, flying through a cloud without any kind of visual reference, possibly getting disoriented. Maybe that influenced the designs of the first attitude reference instruments...?
This is a very interesting subject. The legendary James H Doolittle is credited with the first totally blind flight (including take off & landing) in the history of aviation on 24th September, 1929. He flew the aircraft from "under the hood" & despite his protests was accompanied by a safety pilot in the second open cockpit of the Consolidated NY-2 at the insistence of the authorities.
http://www.afa.org/magazine/1993/1193doolittle.htmlGeneral Doolittle's biography is well worth a read.
Albert Francis Hegenberger made the first solo blind flight at Wright Field. Dayton, Ohio on 9th May, 1932.
http://www.firstflight.org/shrine/albert_hegenberger.cfm