"traineau automobile", and on June 27, 1916, he received the first United States patent for a snow-vehicle using the now recognized format of rear track(s) and front skis. Many individuals later modified Ford Model Ts with the undercarriage replaced by tracks and skis following this design. They were popular for rural mail delivery for a time. The common name for these conversion of cars and small trucks was Snowflyers. Ossipee, New Hampshire claims to be the home of the first snowmobile. In 1917, Virgil D. White set up to create a patent for his conversion kit that changed the Ford Model T into a "snowmobile". He also copyrighted the term "snowmobile". At the time, the conversion kit was expensive, costing about $395. Virgil White applied his patent in 1918 and created his own snowmobile. In 1922, his conversion kit was on the markets and available only through Ford dealerships. In 1935 Joseph Bombardier assembled and successfully tested the first snowmobile. It was a vehicle with a sprocket wheel and a track drive system, and it was steered by skis. The challenges of cross-country transportation in the winter led to the invention of the snowmobile, an all-terrain vehicle specifically designed for travel across deep snow where other vehicles foundered. During the 20th century, rapidly evolving designs produced machines that were two-person tracked vehicles powered by gas engines that enabled them to tow a sled or travel, initially at low-to-moderate speeds, depending on snow conditions, terrain and obstacles protruding above the snow like brush and trees. Where early designs had two-stroke engines, there has been a move toward newer style two and four-stroke gasoline engines, some with over . Multi-passenger snowmobiles The origin of the snowmobile is not the work of any one inventor but more a process of advances in engines for the propulsion of vehicles and supporting devices over snow. It parallels the development of the automobile and later aviation, often inventors using the same components for a different use. Wisconsinites experimented with over-snow vehicles before 1900, experimenting with bicycles equipped with runners and gripping fins; steam-propelled sleighs; and (later) Model T Fords converted with rear tractor treads and skis in front. A patent (554.482) for the Sled-Propeller design, without a model, was submitted on Sept. 5, 1895 by inventors William J. Culman and William B. Follis of Brule, Wisconsin. In the first races held near Three Lakes in 1926,