pounds.[1] The terrific din that these 1800 strokes per minute, given with such force, make in a rock-chamber that is only 8 ft. 3 in. high, and 9 ft. 2½ in. wide, can hardly be imagined; neither can an adequate idea be given of the admirable manner in which the machines accomplish their work. In spite of the noise and the cramped position in which the men necessarily toil on account of the limited space, the work goes steadily forward day and night. Each man knows his part. The foremen direct by signs rather than by words; the labourers guide the chisels; the workmen regulate the supply of air; the machinists are ready in case of accident; slim boys, with long-nosed cans, oil the machinery. Order triumphs in the midst of apparent confusion. One sees now the results of years of perfecting and of practice. Things were very different at the beginning. Then, says M. Conte, "everything was new, not only to the workmen, but also to those who had the direction. . . . The work of perforation was commenced at Bardonnêche on January 12, 1861, but for several days only a single perforatrice was in action, then a second was added, and by the 20th a certain amount of useful work had been done. On the 26th the number of the perforatrices was increased to four, and by working eight hours per day, 10 or 12 holes were made about a yard in depth. On the 12th of February they had perfected about 32 yards of the advanced gallery, which had been left unfinished, and then arrived at the front of the attack. The whole difficulty was there. The number of the machines was again increased, but during ten days there was little result. On the 22d February the works were suspended, in order to make alterations suggested by experience; and it was recommenced on the 2d of March. During the first half of this month an advance of half-a-metre was accomplished in two days, by working seven hours a-day; but towards the end of the month the work had become more easy, and it was possible to perform the whole of the operation in a single day, and to obtain a daily advance of 18 inches to two feet."
- ↑ The perforatrices are independent machines, and one can "be stopped or removed without arresting the progress of the others.
