at a depth of three hundred feet they attained a thickness of three or four inches. Upon examination, it was found that a yellow wax could be made of a portion of this substance, and at once a substitute for wax was manufactured. The discovery caused an excitement like the oil fever of 1865 in America. A large number of leases were made. When I saw the wells of Pennsylvania, in 1879, there were more than two thousand. The owner of the land received one-fourth of the product, and the miners three-fourths. In the petroleum region, the leases at first were whole farms, then they were reduced to 20, then 10, then 5, and at last to 1 acre, which is a square of 209 feet. But in the ozokerite region of Poland, where everything is done on a small scale, when compared with like enterprises in this country, the leases were on tracts thirty-two feet square. These were so small that the surface was not large enough to contain the earth that had to be raised to sink the shaft; consequently the earth had to be transported to a distance, and, when I saw it, there was a mound sixty or seventy feet high. Its weight had become so great that it caused a sinking of the earth, and endangered the shafts to such an extent that the government ordered its removal to a distance and its deposit on ground that was not undermined. The shafts are four feet square, and the sides are supported by timbers six inches through, which leaves a shaft three feet square. The miner digs the well or shaft just as we dig our water wells, and the dirt and rock are hoisted up in a bucket by a rope and windlass. But one man can work in the shaft at a time. For many years no water was found; but, as there is a deposit of petroleum under the ozokerite, at a depth of six hundred feet from the surface, the miners were troubled with gas. This is got rid of by blowing a current of fresh air from a rotary fan through a pipe extending down the shaft as fast as the curbing of timber is put in place. The ozokerite is embedded in a very stiff blue clay for a depth of several hundred feet; below, it is interlaid with rock. [Specimens of crude and manufactured ozokerite were on exhibition, through the kindness of Dr. J. S. Newberry.]