In reply to various correspondents, we beg to state that the information regarding the manufacture of vegetable isinglass in Rouen, which appeared under the head of _A Few French Notes_ in No. 717 of this _Journal_, was taken from _L'Armée Scientifique_, a work compiled by the well-known French savant, M. L. Figuier. As there seems to be some difficulty in reconciling M. Figuier's statements with the present state of the process as carried on in France, we are making further inquiry, and hope to be able to give early and definite information. A FEARFUL SWING. The 'Shaftmen' at our collieries are selected for their physical strength and pluck, in addition to the skill and practical knowledge required for their particular work. The incident we are about to relate will shew how severely the former of these qualifications may at times be tested. The work of these men is confined to the shaft of the pit, and consists mainly in repairing the 'tubbing' or lining of the shaft, stopping leaks, or removing any obstructions interfering with the free passage of the cages up and down the pit. The coal-pit at N---- has a double shaft, divided by a 'bratticing' or wooden partition. These divisions we will call A and B. Two cages (the vehicles of transport up and down the pit) ascend and descend alternately in shaft A. At a certain point the shaft is widened, to allow the cages to pass each other, and their simultaneous arrival at this point is insured by the arrangement of the wire-ropes on the winding-wheels over the pit-mouth. The oscillation of the cages is guarded against by wooden guiders running down each side of the shaft, which fit into grooves in the sides of the cage. On one occasion during a very severe frost these guiders had become coated with ice, and thus their free passage in the grooves of the cages was interfered with. Before this obstruction was discovered, the engine having been set in motion, the downward cage, which fortunately was empty at the time, stuck fast in the shaft before arriving at the passing-point. The ascending cage, whose only occupant was a small boy returning to 'bank,' proceeding on its upward course, crashed into the downward cage in the narrow part of the shaft, where of course there was only a single passage. Though the shock was something terrific, the steel rope was not broken; as the engineman, whose responsible position entails the greatest presence of mind and watchfulness, had stopped the engine on the first indication of an unusual tremor in the rope. Yet such was the violence of the meeting, that both cages, though strongly constructed of iron, were bent and broken--in fact rendered useless--by being thus jammed together in a narrow space. The greatest anxiety was felt as to the fate of the boy, as it was seen that even if he had escaped with his life after such a severe crash, his rescue would be a work of great danger and difficulty.