from a third observing post gave them a second such curve and shewed that the gun must be situated at the point where those curves met. One interesting consequence was the following. Heavy guns are not frequently moved about. They remain in the same position for days and even weeks. So long as a particular gun belonging to the enemy remained in the same position it gave a precisely similar group of three points so that the observers quickly grew to recognize it as though it were a man's signature and thus knowing what particular gun had begun to be busy they could decide on the particular "strafing" that was suitable.
I now turn to the most hateful chapter of the work of Science in War—the introduction of Chemical Warfare. We are slow to realize that an adversary can be utterly destitute of good faith, that the obligations he has undertaken count as nothing in his eyes save as helping to lull the suspicions of others while he is maturing his plans. Hence the first gas attack on April 22nd, 1915 and the five
