An occurrence of considerable interest in this direction took place in a warehouse at Manchester in 1908. In the building were stored several tons of chemicals, among which were twelve tons of chlorate of potash and thirty-two of chlorate of soda. A workman stepping down from a barrel struck fire, and saw a flame, which he tried to extinguish by rubbing with his foot. This, however, had the opposite effect. He then tried a bucket of water, which failed to put it out; he left the building and heard an explosion, followed by a second and a third, all apparently of a violent nature, all three being heard nearly ten miles away, and glass broken throughout a considerable area round the warehouse. The cause appears to have been as follows: During the conveyance of the chlorate into the building leakings took place, and a certain quantity remained on the floor, this mixing with dust and other organic matter would prove a highly sensitive composition. This was ignited by the man’s foot and rapidly spread, probably a deposit which had accumulated under the floor became involved. The woodwork of the building and the wooden barrels then became ignited. The rapid decomposition of the chlorate caused by the heat liberated large quantities of free oxygen, which united with carbon in the smoke to form gas, which exploded upon reaching the correct proportion for so doing. The writer has chiefly confined himself to accidents in firework factories; those occurring during the illegal manufacture of fireworks in premises unlicensed for the purpose present no further interest, and are generally caused by ignorance on the part of the participant of the often extremely dangerous nature of the material he is handling. To take an example: Two boys were engaged in grinding in a mortar a “small quantity” of chlorate of potash and sugar. An explosion resulted which blew out the entire window frames of the room, destroyed the partition between the room and the passage, considerably damaged the other wall, and projected the pestle into the ceiling, where it remained embedded. Accidents at displays are now happily rare; the most fruitful cause of such happenings was the detonation of shell in the mortar, that is, the detonation of the contents or “garniture” by the explosion of the propellant charge. The elimination of chlorate-sulphur composition has reduced the chances of this to a minimum, and the compulsory burying of mortars up to the muzzle has practically eliminated the danger to either firers or spectators. Apart from slight injuries caused by falling rocket sticks and mishaps of a similar nature, accidents to the public at firework displays are things of the past. PART II [Illustration: Types of Modern Fireworks.] CHAPTER I SIMPLE FIREWORKS—ROCKET CLASS