Another case of this nature is the heating up of cases after charging with gerb composition, two of the ingredients of which are sulphur and iron borings, this heating sometimes being sufficient to cause combustion. The cause of this phenomenon is the combination of the iron with sulphur to form sulphide of iron, this action being accompanied by heat. In fact, it is the same as that producing the experiment known as Lemery’s volcano. As far as the knowledge of the writer extends, however, no occurrence of ignition has been definitely traced to this phenomenon, although it seems highly probable that even if ignition of the actual composition has not taken place, cases have occurred where more sensitive compositions have been fired by heat so generated where fireworks have been stored together. The annual reports of H.M. Inspectors of Explosives published since 1876 form an interesting and instructive summary of accidents in explosive trades, an examination of which throws considerable light on our subject. One is struck by the frequency with which explosions occur as a result of ignorance, generally on the part of amateur firework makers. In many cases, as where children are concerned, this ignorance is natural, but the want of knowledge and even reasonable care displayed by individuals whose occupation suggests at least some knowledge of the risk is indeed often extraordinary. Such a case occurred in 1884 in Devonshire, when a local chemist who was illegally manufacturing coloured fire, instructed an assistant to grind in an iron mortar a mixture containing chlorate of potash and sulphur. The lad was killed in the resulting explosion. Even more remarkable was an explosion which took place in a railway carriage in 1893. This was due to the spontaneous ignition of a quantity of chlorate and sulphur coloured fire, which was being carried in an ordinary handbag by a gentleman whose occupation in life was that of professor of chemistry. An accident presenting considerable interest took place in 1885 at Mitcham. The cause of this occurrence was quite simple. A man was fixing the curved stick which forms the pivot upon which a tourbillion rotates to one of those fireworks. The wire nail used for the purpose penetrated the composition and fired it. The remaining goods in the shed were ignited, and communicated to the neighbouring buildings, one of which was a magazine containing 3,000 lbs. of partially manufactured fireworks, including a number of rockets. These being without sticks and becoming ignited flew in all directions, setting fire to other buildings. The result was that ten buildings and an air drying rack were totally destroyed, and three buildings and three racks partially so. This would seem a very serious matter as far as monetary damage is concerned, but as regards the chief consideration in accidents of this kind, that is to say damage to human life and limb, the result was almost negligible; two persons were slightly injured.