In this Tuesday, March 4, 2014 photo is an illustration from a manual by 16th century artillery master Franz Helm at the University of Pennsylvania library in Philadelphia. The manual on artillery and siege warfare depicts a cat and dove strapped with bombs to “set fire to a castle or city which you can’t get at otherwise.” (AP Photo/Matt Rourke)
In this Tuesday, March 4, 2014 photo is an illustration from a manual by 16th century artillery master Franz Helm at the University of Pennsylvania library in Philadelphia. The manual on artillery and siege warfare depicts a cat and dove strapped with bombs to “set fire to a castle or city which you can’t get at otherwise.” (AP Photo/Matt Rourke)
In this Tuesday, March 4, 2014 photo is an illustration from a manual by 16th century artillery master Franz Helm at the University of Pennsylvania library in Philadelphia. The manual on artillery and siege warfare depicts a cat and dove strapped with bombs to “set fire to a castle or city which you can’t get at otherwise.” (AP Photo/Matt Rourke)