Though the earlier gas-masks were manufactured in Brooklyn, and later in Philadelphia, the operations of the division expanded so rapidly that by November, 1917, it became evident that it was no longer practicable for a commercial organization to carry on the manufacture of this new and vitally important article of equipment in the quantities demanded by the new army programme, and it was consequently deemed advisable to establish a government-owned and controlled organization. In pursuance of this policy, the work of mask manufacture was transferred in November to Long Island City, the plant expanding in seven months from a floor space of 157,000 square feet to 1,000,000 square feet, or 23 acres. When the Armistice was signed the Gas Defense Division had a personnel of 274 officers, 2,353 enlisted men, and 13,000 civilians. Much of the work was done by women, and, as a traitor could have worked irreparable damage by tampering with the masks, the employees were selected only after the closest investigation by the Military Intelligence Division of their antecedents and affiliations. From the very outset the officers in charge of mask production conducted a campaign for efficiency based on patriotism. The walls of the factory were hung with copies of a poster depicting a soldier dying from gas as the result of a defective mask; it bore the grim and suggestive title “The Last Inspection.” Lectures and motion-pictures were used to emphasize the horrors of death by gas. And everywhere were placards bearing the admonition: “Remember that _your_ carelessness may cost the life of _your_ husband, _your_ son, _your_ brother.” * * * * * It is not generally appreciated, I think, that gas warfare has tactics all its own. For example: In preparing for an infantry attack the Germans were accustomed to first concentrate all their guns on our batteries. After a brief but intensive bombardment of our artillery positions a portion of the German batteries would abruptly switch their fire onto our infantry, using, of course, a large proportion of gas-shell. Meanwhile the German infantry officers had been notified as to the kinds of gas their batteries were using, and where. Hence, when the German storming troops swept forward they did not wear masks, for their officers knew that a non-persistent gas had been used against the point which was to be attacked. Our troops, being ignorant of this, however, had donned their masks when the first gas-shell came over, and were, therefore, both fatigued and hampered when they were called upon to resist the assault.