It was easier and cheaper for manufacturers to order glass from abroad than to develop its manufacture in this country. Educational and research institutions obtained a large part of their equipment from Germany and offered no special inducement for American manufacturers to provide such apparatus. Duty-free importation favored and encouraged this dependence on Germany for scientific apparatus. With our entrance in the war the European sources of supply for optical glass and optical instruments were cut off abruptly and we were brought face to face with the problem of furnishing these items to the Army and Navy for use in the field. Prior to 1917 only three private manufacturers in the United States had built fire-control apparatus in any quantity for the Government. The Bausch & Lomb Optical Co., Rochester, N. Y., had made range finders and field glasses for the Artillery and Infantry, and gun sights, range finders, and spy glasses and field glasses for the Navy; the Keuffel & Esser Co., Hoboken, N. J., had produced some fire-control equipment for the Navy; the Warner & Swasey Co., Cleveland, Ohio, with J. A. Brashear, Pittsburgh, Pa., had furnished depression-position finders, azimuth instruments, and telescopic musket sights to the Army. The only other source of supply in this country had been the Frankford Arsenal. Prior to 1917 the largest order for fire-control equipment which our Army had ever placed in a single year amounted to $1,202,000. The total orders for such instruments placed by the Ordnance Department alone during the 19 months of war exceeded $50,000,000, while the total orders for fire-control apparatus placed by the Army and Navy exceeded $100,000,000. To meet the situation, existing facilities had to be increased, new facilities developed, and other, allied, industries converted to the production of fire-control material. Quantity production had to be secured through the assembling of standardized parts of instruments which heretofore had either never been built in this country or only in a small, experimental way. A large part of the work had of necessity to be done by machines operated by relatively unskilled labor. The manufacturing tolerances had to be nicely adjusted between the different parts of each instrument, so that wherever less precise work would answer the purpose the production methods were arranged accordingly. Only by a careful coordination of design, factory operations, and field performance could quantity production of the desired quality be obtained in a short time. Speed of production meant everything if our troops in the field were to be equipped with the necessary fire-control apparatus and thus enabled to meet the enemy on even approximately equal terms.