The progress that has been made in the science of mining coal within the last half century bears favorable comparison with the progress that has been made in the other industrial sciences. To-day the ripest experience and the best engineering skill in the land are brought to bear upon the problems connected with coal mining. In comparison with the marked ability employed and the marked success attained in the mining enterprises of to-day, the efforts of the early miners are almost amusing. The pick and the wedge were the chief instruments used in getting out coal. Powder was not thought to be available until John Flanigan, a miner for Abijah Smith, introduced it into the mines in 1818. It is said that when openings were first made for coal in the vicinity of Pottsville shallow shafts were sunk, and the coal was hoisted in a large vessel by means of a common windlass. As soon as the water became troublesome, which was usually as soon as the shaft had reached a depth of twenty or thirty feet, this opening was abandoned, a new shaft sunk, and the process repeated. The mine operator of to-day, having decided upon the shaft as the best method of entry into his mine, sinks it to the bottom of the coal bed, so that its longest dimension shall be with the dip of the seam. Then from each side of the shaft, and at right angles to it, he cuts a passage out through the coal with a width of from ten to fourteen feet. These are the beginnings of the “gangways.” Then from each end of the rectangular foot of the shaft he cuts another passage, at right angles to the first one, about six or eight feet wide, and extending to a distance of from fifteen to thirty feet. These are the first “cross-headings.” At the extremities of the cross-headings passages are now driven parallel to the gangways. These last passages are called “airways.” When the gangways and airways have reached a distance of from sixty to one hundred feet from the foot of the shaft they are united by new cross-headings. It is now apparent that two pillars of coal, each from fifteen to thirty feet wide and from sixty to one hundred feet long are left on each side of the shaft. Larger pillars than these may be left if the roof about the shaft should need more support. It is also apparent, the coal seam being inclined, that the level of one of the airways is higher than the level of the gangway, and the level of the other airway is lower.