Portrait of Col. G.G. Nasmith C.M.G. Head of field laboratories (hygiene) with Canadian Expeditionary Force, World War I. Col. Nasmith confirmed that the gas during 2nd Battle of Ypres was chlorine, and suggested first primitive gas mask.
Col. Nasmith.
On the Fringe of the Great Fight by Colonel George G. Nasmith, C.M.G. Mcclelland, Goodchild &amp; Stewart Toronto 1917. Downloaded from Gutenberg free library.<a rel="nofollow" class="external autonumber" href="http://www.gutenberg.org/files/19876/19876-h/images/frontis.jpg">[1]</a>