With almost a total lack of optical glass in this country, with an equal lack of factories and workmen familiar with military optical instrument-making, we were suddenly called upon to produce about 200 different types of instruments in large quantities. These included many new designs of fire-control apparatus made necessary by new artillery developments both among the allies and in our own factories, by the adoption of trench warfare in place of open warfare, by the development of weapons for use against aircraft, by the extension of indirect fire-control methods to weapons which formerly had been fired by direct sighting, and by the use of railway and seacoast artillery. While we did not solve all the difficulties in this development, we had met and conquered the worst of them, and we were making such great strides in production when the war ended that all the requirements of the Army would have been met early in 1919. It has been a source of inspiration to witness the high sense of patriotic duty and cooperation shown by the manufacturers which made possible the remarkable expansion of the optical glass and instrument industry in the United States during the period of the war. The following table shows the principal items of sights and fire-control apparatus, the firms that did the work, the quantity of the various kinds of instruments ordered, and the deliveries made up to November 11, 1918, and to February 20, 1919: --------------------+---------------------------+---------+----------------- | | | Deliveries to-- Material. | Firm. | Total +--------+-------- | | ordered.|Nov. 11,|Feb. 20, | | | 1918. | 1919. +-------------------+---------------------------+---------+--------+--------- Aiming circle, |Spencer Lens Co., | 1,473 | 717 | 1,117 model 1916 | Buffalo, N. Y. | | | | | | | Do. |Frankford Arsenal, | 98 | 98 | 98 | Philadelphia | | | | | | | Aiming stakes |J. C. Deagan Co., | 16,618 | | 1,320 for machine gun | Chicago, Ill. | | | | | | | Aiming posts, |Metropolitan Manufacturing | 16,791 | 25 | 250 field artillery | Co., Detroit, Mich. | | | | | | | Do. |Dahlstrom Metallic Door | 10,791 | | | Co., Jamestown, N. Y. | | |