Pattern does not specify yarn weight, gauge or size. Hook size given as “No. 4 Woolco hook”, which I am not sure if it means a 4 mm hook or some other size by a system used by Woolco in 1916.
New guess at hook size, might be US size “E/4”, which translates to 3.5 mm.
Also available here: http://www.archive.org/details/cu31924085657306