The smooth-bore cannon used by the Filipinos during the Battle of Zapote River in 1899.
Unknown US Army photographer
University of Michigan Library: <a rel="nofollow" class="external free" href="http://quod.lib.umich.edu/s/sclphilimg/x-516/PHLA542?chaperone=S-SCLPHILIMG-X-516+PHLA542;evl=full-image;g=southeastasia-icgr;lasttype=boolean;lastview=thumbnail;quality=1;resnum=5;start=1;subview=detail;view=entry;rgn1=sclphilimg_all;select1=all;q1=zapote">http://quod.lib.umich.edu/s/sclphilimg/x-516/PHLA542?chaperone=S-SCLPHILIMG-X-516+PHLA542;evl=full-image;g=southeastasia-icgr;lasttype=boolean;lastview=thumbnail;quality=1;resnum=5;start=1;subview=detail;view=entry;rgn1=sclphilimg_all;select1=all;q1=zapote</a>