April 21 (Wed.)
The Germans are driven from 'Hill 60' (see May 5).
April 22 (Thur.)
The Second Battle of Ypres (see May 24) begins; poison gas is used by the Germans for the first time; the Canadians suffer heavily.
April 24 (Sat.)
A second German gas attack; the Germans storm St. Julien.
April 25 (Sun.)
Alsace:—The French lose ground on the Hartmannsweilerkopf.
April 25-26 (Sun.-Mon.)