284 Ml'. A. Normandy on the Spheroidal State 



I have already had the honour to relate to you that I had seen 

 the plates of a Cornish boilei-, a quarter of an inch thick, become 

 red-hot in the flue, although at the time the boiler contained its 

 due quantity of water. It was a new boiler, about 18 feet long ; 

 and that the water had assumed therein the spheroidal state is 

 proved by the fact, that a lead rivet, ] inch in diameter, put in 

 for safety was actually melted. It is, in fact, this rivet which 

 led to the detection of the cause of the occurrence, and an inves- 

 tigation of the subject brought out the following details. The 

 fireman or stoker was an ignorant mulatto, who having noticed 

 the lead rivet in the boiler, had given it as his opinion that it 

 would soon be melted by the fire ; the possibility of such an 

 accident having been denied by one of his fellow-workmen, a bet 

 had taken place between them. The wager having thus been 

 laid, the fireman set to keeping up a brisk, bright fire ; in con- 

 sequence of which, steam being generated exceedingly fast, p7'i- 

 ming, that is, a production of steam under the superincumbent 

 water, took place, and, as a matter of course, the water, or a por- 

 tion thereof, not being any longer in contact with the surface of 

 the iron plate, the latter in a A'ery short time became red-hot, 

 and the rivet melted; for some time afterwards, however, the 

 water being in the spheroidal state, the boiler remained appa- 

 rently sound, that is, it did not leak, although it had an opening 

 of an iuch diameter left in consequence of the melting of the 

 rivet ; it is only shortly afterwards I was told, that the heat 

 having diminished, torrents of water poured through the hole 

 with almost explosive violence, emitting volumes of scalding 

 steam as it came in contact with the fire on the grate. 



This took place at the Wenlock Timber Saw-mills ; and I can 

 bear testimony to the above fact, and likewise to this circum- 

 stance, that when filled as usual with its normal quantity of 

 water, the bottom of the boiler over the fire could, in the course 

 of five or six minutes, be made red-hot at pleasure by brisk 

 fii'ing. In fact, having called at the above works, according 

 to appointment, to meet the engineer there, my inquiry as to 

 the then state of the boiler was answered by the foreman, in 

 presence of his master, in these words : — " The boiler is not red- 

 hot now, but if you will step this umy it ivill be made so immedi- 

 ately ;" and in spite of all remonstrance as to the danger of such 

 an experiment, he came shortly afterwards to announce that the 

 boiler was red-hot, and / saw if in that state in presence of the 

 engineer, the master, his nephew, the foreman, and the fireman 

 or stoker. The production of steam had been thereby sponta- 

 neously reduced, the bolt or lead rivet eventually melted, but 

 not in my presence ; for seeing the state of things, I speedily 

 retreated with the engineer and the master, but almost reluct- 



