The adoption for our own manufacturing programme of the British types of heavy howitzers entailed no unusual complication, but the adoption of the French types of field-guns and light howitzers introduced a factor whose importance the lay mind had theretofore not fully realized. I refer to the French use of the metric system, in which, of course, all the plans, specifications, and drawings furnished us by the French were figured. One inch = 2.54001 centimetres. The full significance of this difference in the national units of measurement is not apparent until one reflects that not a single standard American drill, reamer, tap, or die will accurately produce the results demanded by the specifications on a French drawing. Furthermore, the French standards for bar stock, for rolled sheets and plates, for structural steel shapes such as angles and I-beams, even for rivet-holes and rivet spacing, are far different from American standards. Given complete, up-to-date drawings of French material (and in many cases these were not obtainable), the Ordnance engineer was immediately confronted with the necessity of either changing the American shop equipment—drills, reamers, taps, dies, and the like—to conform with French standards of measurement, thereby discarding the advantage of quick procurement of standard rolled stock, bolts, nuts, rivets, cotter-pins, or of doing what he did do—translating the centimetres in which the French specifications were figured into inches. But this was by no means all. French industrial practice develops the highly skilled all-round machinist to whom is left considerable discretion in determining finished dimensions and in fitting assembled parts; American industrial practice develops the machine specialist who works to tolerances—to maximum and minimum gauges—and whose output accordingly requires little or no hand-fitting of assembled parts. The French mechanic always sees the complete assembled unit; the American confines his attention to the particular component on which he is engaged and the gauges which check the accuracy of his work. So, in translating the French drawings, they had to be adapted not only to the material phase of American shop practice, but the personal equation of the American workman had also to be considered. Tolerances had to be prescribed, limit gauges had to be provided, jigs and fixtures, special milling cutters, and a hundred other tools and instruments had to be designed and manufactured. But our manufacturing difficulties did not end even there. Though the French gave us the drawings of even their most jealously guarded secret devices, they could not give us that intangible something which, for want of a better term, I can best describe as innate mechanical skill of so high an order that it approaches genius, which is so marked a characteristic of the best French artisans and mechanics. Take, for example, the problem involved in the manufacture of the hydropneumatic