76 Proceedings of the Royal Physical Society. 



in this instance of spontaneous combustion is the uninflam- 

 mable, nature of this mineral. I put a piece of it in the 

 midst of a strong furnace in full blast, and yet it would 

 hardly inflame. Following up my investigations, I made an 

 analysis of the mineral, which showed that it contained a 

 considerable proportion of iron sulphide, with some carbona- 

 ceous matter, which substances becoming oxidised by the in- 

 fluence of air and moisture, had produced heat sufficient to 

 inflame the mass. I produce a small portion of the mineral 

 which has been subjected to the heat of the furnace, from 

 the appearance of which you may form an estimate of the 

 amount of heat which would be necessary to set the mineral 

 on fire. 



The second instance occurred in a railway waggon, and the 

 material which inflamed was woollen yarn. I am aware that 

 cotton waste, etc., has been known to catch fire, and in fact 

 is an easily ignitible substance, but this woollen yarn is by 

 no means of this nature. I put a piece of red-hot iron into 

 a bundle of it, and this caused a slight singeing, but nothing 

 more ; and even when the yarn was set on fire by being held 

 in the centre of a flame, it did not, as a rule, continue to 

 burn — all signs of burning disappearing shortly after the 

 source of heat was removed, and yet there is no doubt this 

 material ignited spontaneously. When I first saw it, it was 

 lying in a railway truck deluged with water. It had ignited 

 some hours previous to my visit, and in order to extinguish 

 the fire the contents of the truck had been subjected to a 

 flood of water obtained from the hydrants used for replenish- 

 ing the water cisterns of the locomotives. After carefully 

 inspecting the half-burned bales, I ordered them to be covered 

 up again until I got an analytical examination of the yarn 

 made. In the course of the next day or two, although de- 

 luged with water, it again threatened to ignite. The chemical 

 examination of this material revealed the presence of a small 

 proportion of fatty matter, which, by becoming oxidised, had 

 produced, I have little doubt, the heat — great as it must have 

 been — which caused the conflagration. 



I hope again to renew my experiments on this subject, the 

 result of which will be communicated to the Society. Espe- 



