50 REPORT — 1841. 



melted, and was followed by a loud escape of elastic matter. Tlie engine stopped 

 working, and on bringing a lighted match into the escapage, it took fire, and burnt 

 with the lambent flame of hydrogen gas. The author's impression was, that the 

 escaping vapour was not pure hydrogen. Water condensed on a piece of cold iron 

 held in the flame, but no water condensed on the cold iron after the flame was ex- 

 tinguished. On examining the boiler, all the tubes were found fed-hot. This 

 experiment was repeated with many modifications. The temperature of the escaping 

 vapour was ascertained by means of bars, previously prepared to melt at different 

 temperatures ; these indicated a temperature of about 400°. In about eight minutes 

 a piece of pure lead melted — woollen cloth was charred, and a piece of tow held in 

 the escapage took fire. In other experiments it was found that the pipes became 

 sufficiently hot to explode gunpowder and many chemical preparations. 



Having satisfied himself of this property of heated steam or elastic matter, formed 

 from the last portions of water in a boiler, the author proceeded to examine, as far as 

 possible, its chemical nature — to determine whether any decomposition, or new ele- 

 mentary formation, took place. He found that the elastic matter was not conden- 

 sable over cold water, and would not in many cases burn, or show any indications of 

 the presence of hydrogen, or other inflammable matters. In some experiments 

 it was found to extinguish flame. The experiments with copper vessels afforded the 

 same results as those manufactured from iron. From these experiments it appeared, 

 that whenever the heating apparatus falls short of water, the elastic matter formed 

 over the fire will carry sufficient heat through close pipes, to any distance, to set fire 

 to wood and other combustible bodies, and that whether the hot-water apparatus be 

 under pressure or not, or whether the heating surface be of tubes, plates, or cylin- 

 ders. On the other hand, it would further appear, from some experiments enume- 

 rated, that in no case is there danger when a given quantity of water is present. 

 Mr. Gurney suggests, that if both ends of the circulating series in hot- water appa- 

 ratus, namely, the part which immediately goes from the heating surface beyond the 

 furnace, and that part where the circulation returns to it before it enters the furnace, 

 were made of a metal which would not melt at the fair working temperature of the 

 water, but which would melt at a temperature of from 500 to 600° of heat (say lead 

 pipe), there would be little, if any, danger from fire. 



On Spontaneous Combustion. By A. Booth, F.L.S. 



The author stated that he had nothing novel to offer either in the way of theory or 

 facts, but simply to draw attention to a long series of circumstances in well recorded 

 and authenticated instances. These were scattered throughout the various scientific 

 and public records, and had never been collected into any form. From his inquiries he 

 was satisfied that many fires originated from the phsenomenon of spontaneous com- 

 bustion, and he considered it highly proper that persons should be put upon their 

 guard with respect to the operations of an insidious danger. He commenced by noti- 

 cing pigeons' dung, which was known at a very remote date, as Galen observed that 

 pigeons' dung takes fire when it becomes rotten, and that the dung of a pigeon was 

 sufficient to set fire to a whole house. This is further confirmed by Father Casati, a 

 Jesuit, who relates to have been informed, that from the great quantities of the dung of 

 doves, large flights of which used for many ages to build under the roof of the great 

 church of Pisa, sprung originally the fire which consumed the said church. Cases 

 had been also recorded of dung-hills and stable litter, turf and peat, corn, wheat-flour, 

 oatmeal, torrefied vegetable substances, as saw-dust, roasted coffee and chocolate nuts, 

 beans, peas and lentiles, and charred or heated vegetable substances, malt and torre- 

 fied bran, the latter of which was much used in different parts of Germany as an 

 external application for diseased cattle. He also adduced instances of madder, saf- 

 fron, ha}', charcoal, charcoal and coal ashes, lamp-black, coal, nitric acid packed in 

 saw-dust, tan, vegetables boiled in oil or fat, wool, wool combings, woollen cloth, 

 woollen stuffs, cotton, cotton goods, cotton prepared for dyeing, waste cotton in 

 manufactories, candlewick yarn in imitation of cotton yarn, hemp and flax, oakum 

 and linseed oil, hempen fibres and oil, drying oils, cere cloth or oiled canvass, sail- 

 cloth, rags, paper, paint, cloth used in wiping paint-brushes, &c. Mr. Booth said 

 that his attention was strongly impressed upon these circumstances some years back, 

 on account of the execution of a young man named James Butler, on suspicion of 



