 This Passing Parade series entry looks at three seemingly innocuous items that are contributing to the war effort: 1) When billiard ball manufacturers were searching for a substitute for ivory, they had no idea that celluloid would lead to the plastics used in today s airplanes, warships, and other items; 2) A scientist discovers that when collodion evaporates, it leaves a residue that keeps glass from shattering. This discovery led to the safety glass used in car windshields and, more important, in the cockpit windows of combat pilots; 3) The silk strands spun by spiders proved to be the best material for cross hairs in sights in periscopes and bomb sights.