to twenty feet of soil. Any experienced miner can tell when the face of the breast is approaching the outcrop; the coal becomes softer, changes in color, breaks into smaller pieces, sometimes water runs down through. It is obviously unsafe to erect buildings on the line of this outcrop, or immediately inside of it, where the roof is thin. There is no assurance that the body of coal left will not slip down the breast; and the pillars of coal near the surface are so soft that any disturbance of this kind may cause them to give way and let down the entire thickness of strata above them. This was what occurred at the Stockton mines near Hazleton on December 18, 1869. Two double tenement houses were situated over the face of a worked-out breast, near the outcrop. About five o’clock in the morning the roof fell, carrying both houses down with it a distance of about eighty feet into the old breast. The inhabitants of one of the houses escaped from it a moment before it went down, those in the other house, ten in number, were carried into the mine, and were killed. The buildings in the pit took fire almost immediately, and rescue of the bodies crushed there among the débris was impossible. [Illustration: GANGWAY IN KOHINOOR COLLIERY, NEAR SHENANDOAH, PA.] Accidents of this class are happily very rare. The exercise of ordinary judgment is sufficient to prevent them. The list of disasters due to falls of roof at the faces of chambers might, as has already been explained, be greatly reduced by the same means. But it is often impossible to prevent, or even to guard against, those falls which cover a large area, though their coming may be heralded for days by the working of pillars and all the indications of a squeeze. This was the case at the fall in the Carbondale mines in 1846, one of the most extensive falls that has ever been known. It covered an area of from forty to fifty acres, fourteen persons were killed by it, and the bodies of eight of them were never recovered. Although this disaster occurred more than forty years ago, the writer had the privilege, in the summer of 1888, of hearing an account of it from one of the survivors, Mr. Andrew Bryden. Mr. Bryden is now, and has been for many years, one of the general mining superintendents for the Pennsylvania Coal Company, with headquarters at Pittston, Pennsylvania. His story of the fall is as follows: “This disaster occurred on the twelfth day of January, 1846, at about eight o’clock in the forenoon. It was in Drifts No. 1 and No. 2 of the Delaware and Hudson Canal Company’s mines at Carbondale. The part of the mine in which the caving in was most serious was on the plane heading, at the face of which I was at work. We heard the fall; it came like a thunderclap. We felt the concussion distinctly, and the rush of air occasioned by it put out our lights. I and those who were working with me knew that the fall had come, and we thought it better to try immediately to find our way