Page:Report from the Select Committee on Steam Carriages.pdf/60



Mr. G. Gurney. 5 August, 1831. . The only one acknowledged in this country is that forming water. A compound of two proportions in volume of oxygen and two of hydrogen, has been chemically combined in Paris, although I believe we never have succeeded publicly in this country.—This compound was highly explosive when brought in contact with certain substances. It would be by expansion?—By chemical contact; if brought into contact with certain substances, it would be so affected as to produce explosion. I have reason to believe from some original experiments, that there is a compound of these elements produced under certain circumstances in steam boilers. The want of water in a boiler is favourable, in which case the temperature is raised and the compound formed; the bursting of boilers I believe frequently takes place, from this compound coming in contact with substances that will decompose it, and perhaps I might mention this fact, as it is a very interesting one, namely, that boilers often burst when the valves are known to blow at a pressure very considerably lower than the boiler has been proved to.

Does not that take place also when the water is in the boiler?—If the water is low in the boiler it will take place; if it is high, never.

Has it not frequently happened that boilers that were calculated for a higher pressure, have even burst at a lower pressure than they were intended for, when water is in them?—When water is high in them, never; but when it is so low in them as to form this chemical compound, it does. I would state a fact, which was mentioned to me by my friend Sir Anthony Carlisle, which throws considerable light upon the subject, and first led me to my suspicions and experiments respecting it. The case was, that a boiler at Mr. Meux's brewery, with an open top—a common cauldron—burst with a violent explosion. I believe one man was killed, and two very severely scalded. There was no cover at all on the vessel. This phenomenon, upon inquiry, appeared to be occasioned be gelatinous matter, forming a crust, a film, or blister, and prevented the contact of water with the bottom of the