Out of the 250 gases prepared by the Offense Chemical Research Section, very few were sufficiently valuable to pass all of these tests and thus the number of gases actually put into large scale production were less than a dozen. This had its advantages, for it made unnecessary a large number of factories and the training of men in the manufacturing details of many gases. As one British report stated, “The ultimate object of chemical warfare should be to produce two substances only; one persistent and the other non-persistent; both should be lethal and both should be penetrants.” They might well have added that both should be instantly and powerfully lachrymatory. Since most of the work of the Research Division will be covered in detail in later chapters, only a brief summary of the principal problems will be given here. The first and most important problem was the development of a gas mask. This was before Sections had been organized and was the work of the entire Division. After comparing the existing types of masks it was decided that the Standard Box Respirator of the British was the best one to copy. Because we were entirely new at the game that meant work on charcoal, soda-lime, and the various mechanical parts of the mask, such as the facepiece, elastics, eyepieces, mouthpiece, noseclip, hose, can, valves, etc. The story of the “first twenty thousand” is very well told by Colonel Burrell.[12] [Footnote 12: _J. Ind. Eng. Chem._, =11=, 93 (1919).] “THE FIRST TWENTY THOUSAND “About the first of May, 1917, Major L. P. Williamson, acting as liaison officer between the Bureau of Mines and the War Department, put the last ounce of ‘pep’ into the organization by asking us to build 20,000 gas masks for shipment overseas. 20,000 masks did not seem like a very large order. We did not fully appreciate all the conditions which a war gas mask had to encounter, so we readily and willingly accepted the order. Then began a struggle with can manufacturers, buckle makers, manufacturers of straps, rubber facepieces, eyepieces, knapsacks, etc. The country was canvassed from the Atlantic Coast to the Mississippi River for manufacturers who could turn out the different parts acceptably and in a hurry. “Charcoal was made from red cedar by the Day Chemical Co. of Westline, Pennsylvania; soda-lime permanganate was manufactured by the General Chemical Company; knapsacks by the Simmons Hardware Company in St. Louis; facepieces by the Goodrich and Goodyear Rubber Companies at Akron; canisters by the American Can Company; and the assembly made at one of the plants of the American Can Company in Long Island City.