to a place of safety and the parties who supplied them immediately notified thereof. The car containing explosives must be labelled as such in a conspicuous manner and must be hauled as near the middle of the train as possible, and must not be placed next to a car containing oil or inflammable material. A flying switch must not be taken with explosives. In case of a wreck every precaution must be taken to prevent fire. While most of the high explosives burn quietly when lighted in small quantities, and without causing disastrous explosions, it must be remembered that it is not a safe experiment. =Storage.= Local conditions have much to do with the type of structure to be built for an explosives’ magazine. In general, it may be said that the lighter the construction the better. The laws of some countries require that all magazines be built of such material, and in such a manner, that in the event of an explosion the building will be completely disintegrated and no pieces thrown to any great distance. Storage in caves, tunnels, earth or stone-covered vaults, and in log structures, should under no circumstances be tolerated. The chief objection in all these cases is that the structure will hold dampness, and any dampness in a magazine containing explosives into which nitrates enter as an essential or accessory ingredient, is certain to affect its quality and render it more or less dangerous in subsequent use. This applies to gunpowder and to practically all dynamites, especially those made in America. It does not apply to Kieselguhr Dynamite of foreign manufacture. When it is desired to protect a magazine from rifle fire, the magazine may be banked with earth to an extent that would be proof against bullets, and to a height well above the cases as arranged in the magazine; arrangements being made for perpendicular air-shafts through the embankment next to the outer wall at intervals necessary to give the required ventilation; ventilating shafts being screened with fine wire netting to exclude vermin and constructed in such a manner that water cannot enter. Explosives should be stored in tiers, box on box, with laths between to prevent dampness accumulating. No cases must be opened in the magazines, a separate building being provided at a safe distance for that purpose. Gunpowder and dynamites in unopened cases, and fuses securely boxed, may be stored in the same magazine, but no fulminates in the form of caps, or otherwise, or loose coils of fuse, should ever be stored in the same building with gunpowder and high explosives. It is important that the magazine be kept clean, and that no men with nails in their boots be allowed to work in a magazine. No fires should be lighted or smoking allowed in or about a magazine containing high explosives. LECTURE II. EXPLOSIVES. Classification, Characteristics and Properties. =General Classification.= Explosives are classified generally as follows:-- 1. Explosive mixtures of the nitrate class.