Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne 1838 Vol.2.djvu/418

 the top of the A pit; under these circumstances, the B Pit furnace could not be lit with safety. It therefore became necessary to shorten the run of the C Pit air to such an extent as to enable the water-fall to reduce it below the firing point, and to carry off that part which could not be so diluted by the pipe drifts and dumb furnace.

This plan succeeded, and on the morning of the 21st of August the two furnaces were lit up, without the slightest accident. It was of importance that the furnaces in the two up-cast pits should be lit at the same moment ; the best mode of effecting which was, a desideratum, as the old mode, by running a red-hot ring of iron down a line from the surface into the furnaces was impracticable, owing to the distance at which they were placed from the bottoms of the pits.

My friend, Major Emmett, of the Royal Engineers, who took great interest in our operations, and from whom I received many valuable hints during their progress, suggested the idea of lighting them by the aid of a piece of quick and slow match, such as is used in the artillery service. I carried this hint into effect in the following manner : — A piece of French slow match, of sufficient length to burn twenty-seven minutes, was attached to a piece of quick match of five or six inches in length, with a piece of mealed gunpowder secured in a paper case at the point of junction. The furnaces being made on with a cold fire of dry wood, tarred rope, and coals, an apparatus of the above description was placed in each. The slow matches were fired at the same instant, the time being regulated by stopwatches ; the common artillery slow match being used for that purpose, which allowed sufficient time for the parties employed in the operation to get to bank before the quick match was ignited.

The interval of time between the lighting of the slow match, and the appearance of the smoke from the furnaces, was watched with great anxiety. And as nearly as possible to the time calculated, we had the satisfaction of seeing the smoke begin to appear at the top of the up-cast pits, and presently afterwards to discharge freely, which shewed that the furnaces were effectually ignited, and that the return air from the workings was not inflammable. In a couple of hours the furnaces were renovated with fresh coals, and the return currents of air to both were found remarkably