In all six shots were fired, five of which were for the purpose of winning coal, while the sixth was expressly arranged as a "blowout shot." The roburite--which resembles nothing so much as a common yellow sugar--is packed in cartridges of about 41/2 in. in length and 11/2 in. in diameter, each containing about 65 grammes (one-seventh of a pound) inclosed in a waterproof envelope. By dividing a cartridge, any desired strength of charge can be obtained. The first shot had a charge of 90 grammes (one-fifth of a pound) placed in a hole drilled to a depth of about 4 ft. 6 in., and 13/4 in. in diameter. All the safety lamps were carefully covered, so that complete darkness was produced, but there was no visible sign of an explosion in the shape of flame--not even a spark--only the dull, heavy report and the noise made by the displaced coal. A large quantity of coal was brought down, but it was considered by most of the practical men present to be rather too much broken. The second shot was fired with a single cartridge of 65 grammes, and this gave the same remarkable results as regards absence of flame, and, in each case, there were no noxious fumes perceivable, even the moment after the shot was fired. This reduced charge gave excellent results as regards coal winning, and one of the subsequent shots, with the same weight of roburite, produced from 10 to 11 tons of coal in almost a solid mass. It has been found that a fertile cause of accidents in coal mines is insufficient tamping, or "stemming," as it is called in Yorkshire. Therefore a hole was bored into a strong wall of coal, and a charge of 45 grammes inserted, and very slightly tamped, with the view of producing a flame if such were possible. This "blowout" shot is so termed from the fact of its being easier for the explosion to blow out the tamping, like the shot from a gun, than to split or displace the coal. The result was most successful, as there was no flash to relieve the utter darkness. The second set of experiments took place on October 24 last, in the Monk Bretton colliery, near Barnsley, of which Mr. W. Pepper, of Leeds, is owner. This gentleman determined to give the new explosive a fair and exhaustive trial, and the following programme was carried out in the presence of a very large gathering of gentlemen interested in coal mining. The chief inspector of mines for Yorkshire and Lincolnshire, Mr. F.N. Wardell, was also present, and the Roburite Explosives Company was represented by Lieut.-General Sir John Stokes, K.C.B., R.E., chairman, and several of the directors. 1. _Surface Experiments._--A shot fired on the ground, exposed. This gave no perceptible flame (70 grammes of roburite was the charge in these experiments). 2. A shot fired on the ground, bedded in fine coal dust. No flame nor ignition of the coal dust was perceptible.