Source: Gathering Our Heroes.
Find-A-Grave
Family Search: Private William Robertson was born on 7 February 1874, in Cairnie, Aberdeenshire, Scotland, United Kingdom as the son of James Robertson Jr and Jane Morrison. He had at least 2 sons and 1 daughter with Mary Gibb Smith. He immigrated to Canada in 1913 and lived in Chatham, Kent, Ontario, Canada for about 8 years. He registered for military service in 1916. In 1916, at the age of 42, his occupation is listed as labourer, grand trunk railway in Chatham, Kent, Ontario, Canada.
History of the 18th Battalion CEF, "The Fighting Eighteenth" 