This Day in Auto History:

5.12.1904 The first and only speed trials staged at Douglas Promenade, Isle of Man are won by S. F. Edge in a Napier at 57.3 mph 5.12.1915 Automotive historian Lyle Kenyon Engel is born in New York City 5.12.1922 Racer Roy Francesco Salvadori is born in Dovercourt, Essex, England of Italian ancestry 5.12.1935 The Alfa Romeo 16-cylinder Bimotore race cars debut at the 9th Tripoli Grand Prix in Libya, with two cars driven by Tazio Nuvolari and Louis Chiron finishing 4th and 5th 5.12.1946 William F. Marande, Chief Metallurgist of the Eaton Manufacturing Company and a former employee of Buick, dies in Saginaw, MI at age 46

Source: Automobile History Day By Day, by Douglas A. Wick