Nearly 4,000 troops destined for battle in Europe's First World War had come from Sacramento and other cities within the county; of those 4,000, about 100 died. The coming of the war also sparked hysteria amongst the population, biasing them against Germans and concepts associated with Germany. Sacramento's Lutheran churches began to preach in languages other than German. Additionally, a Council of Defense searched for and punished signs of disloyalty to the American cause. City tensions increased with the bombing of the governor's mansion in 1917, and suspects affiliated with the Industrial Workers of the World militant party were detained and jailed, although never convicted. When the war ended in 1918, the city celebrated the return of the 363rd Infantry regiment of the 91st Division and the visit of president Woodrow Wilson, who arrived to advocate his League of Nations proposal in 1919 in the face of staunch opposition headed by Governor Johnson and "Sacramento Bee" editor Charles Kenny McClatchy. The coming of the 1917 American intervention in World War I exponentially increased demand for Curtiss JN-4 biplanes. A contract with the government led to the opening of Mather Air Force Base in the county, and Sacramento grew to rely on the biplanes for continued economic growth up until the end of the war. Surplus military equipment, including the biplanes, were put to use by the Sacramentan populace. In 1929, farmers in the Sacramento area experimented with crop seeding via aerial means; notably, Chinese revolutionary Sun Yatsen, with assistance from Delta farmer Jack Chew, purchased ten surplus aircraft and held sessions for maneuver practice from a local alfalfa field with local Chinese pilots. A growing civilian fascination with aviation in the era was fed by the numerous air shows that were held around the Sacramento area.