The Italian steamer Alessandra was sunk off the Island of Madeira April 2. The Ministre de Smet de Naeyer, a Belgian relief ship, was sunk in the North Sea on April 6, and twelve members of the crew were lost. As a result of the commercial agreement between Spain and the United States, German submarines began a blockade of Spanish ports, April 11. Because a German submarine had captured a Uruguayan military commission bound for France, the Government of Uruguay on April 11 asked Berlin, through Switzerland, whether it considered that a state of war existed with Uruguay. CAMPAIGN IN WESTERN EUROPE March 18--Belgians repulse German raids in the region of Nieuport, Dixmude, and Mercken. March 19--French penetrate German line near Rheims; British carry out successful raids in the neighborhood of Villers-Guislain, La Vacquerie, and Bois Gienier. March 20--German airplane drops balls of liquefied mustard gas on American lines northwest of Toul; Americans shell Lahayville, causing a heavy explosion and forcing the Germans to retreat; French repulse violent raids in the Souain sector of Champagne. March 21--Germans open terrific drive on British lines on a fifty-mile front from southeast of Arras as far as La Fère; French lines bombarded north and southeast of Rheims as well as on the Champagne front; Paris bombarded by long-range guns. March 22--Germans claim 16,000 prisoners in big drive; General Haig reports them gaining at some points and repulsed at others; American artillery fire destroys German first and second line trenches east of Lunéville; violent gun duels in the Aisne and Champagne sectors; French repulse three German raids near Souain. March 23--Germans smash British front, win victories near Monchy, Cambrai, St. Quentin, and La Fère, and penetrate into second British positions between Fontaine les Croisilles and Moeuvres; British evacuate positions in the bend southwest of Cambrai; Germans penetrate third British position between the Omignon stream and the Somme; Paris again shelled by gun seventy-five miles away; ten persons killed and fifteen or more wounded; fierce artillery fire on the French front from the Oise River to the Vosges Mountains. March 24--Germans capture Péronne, Chauny, and Ham, and cross the River Somme at certain points south of Péronne; assaults further north repulsed; Paris again bombarded by gun located in the Forest of St. Gobain. March 25--Germans take Bapaume, Nesle, Guiscard, Biaches, Barleux, and Etalon; French take over sector of British battlefront south of St. Quentin and around Noyon; General Pershing announces that two regiments of American engineers are on the Somme battlefield; long-range bombardment of Paris continues; one long-range gun explodes, killing ten men; American gunners shell St. Bausant and the billets north of Boquetau.