With this knowledge at hand we adopted for our own program certain French types of field guns and howitzers and British types of heavy howitzers. The reproduction of the British types caused no unusual difficulties, but the adoption of French plans brought into the situation a factor the difficulties of which are apt not to be appreciated by the uninitiated. This new element for consideration was the circumstance that the entire French system of manufacture in metals is radically different from our own in its practices and is not readily adapted to American methods. The English and the American engineers and shops use inches and feet in their measurements, but the French use the metric system. This fact means that there was not a single standard American drill, reamer, tap, die, or other machine-shop tool that would accurately produce the result called for by a French ordnance drawing in the metric system. Moreover, the French standards for metal stocks, sheets, plates, angles, I-beams, rivet holes, and rivet spacing are far different from American standards. It was discovered that complete French drawings were in numerous cases nonexistent, the French practice relying for small details upon the memory and skill of its artisans. But even when the complete drawings were obtained, then the American ordnance engineer was confronted with the choice of either revolutionizing the machining industry of the United States by changing over its entire equipment to conform to the metric system, or else of doing what was done--namely, translating the French designs into terms of standard American shop practice, a process which in numerous cases required weeks and even months of time on the part of whole staffs of experts working at high tension. Nor do the French know the American quantity-production methods. The French artisan sees always the finished article, and he is given discretion in the final dimensions of parts and in the fitting and assembling of them. But the American mechanic sees only the part in which he is a specialist in machining, working with strict tolerances and producing pieces which require little or no fitting in the assembling room. Consequently, in the translating of French plans it was necessary to put into them what they never had before, namely, rigid tolerances and exact measurements. [Illustration: FIGURE 1.