46 Perkins? Steum Engine: 



tion of so many absurd things respecting my engine ; I had 

 no knowledge of these publications, and of course had no 

 controul over them. Indeed I have been extremely cautious 

 about publishing any thing myself, or sanctioning it in others; 

 my determination having been first to complete the essential 

 improvements of which I have been in pursuit. I presume 

 that you have seen my last paper on the compression of wa- 

 ter, air, &c. Its publication by the Royal Society, has cre- 

 ated no small sensation among the philosophers of the old 

 school. The council would not have allowed the reading of 

 it, had not Dr. Wollaston and Sir Humphrey Davy witnessed 

 many of the experiments. I shall soon publish an experiment 

 with which I think Dr. Hare will be pleased, as it will, if I 

 mistake not, prove practically, what the doctor has so ably 

 attempted to establish theoretically, namely, that caloric is 

 matter. The proof is simple and direct, and I am persuaded 

 that when you see it, you will think it conclusive. I was led 

 to the discovery of this fact by my experiments upon steam ; 

 the results of many of which have been very extraordinary, 

 and quite unexpected. One of the most striking, is the great 

 repellent power of heat. I discovered that a generator, at 

 a certain temperature, although it had a small crack in it, 

 would not emit either water, or steam. This fact I mention- 

 ed to a very scientific friend, who questioned its accuracy, 

 and to convince him, I tried the experiment ; but he conclu- 

 ded that the expansion of the metal must have closed the 

 fissure. To remove every doubt, I proposed to drill a small 

 hole through the side of the generator, which was according- 

 ly done. After getting the steam up to a proper tempera- 

 ture, I took out the plug, and although we were working the 

 engine at thirty atmospheres, nothing was seen, or heard to 

 issue from the plug hole ; all was perfectly quiet ; I next low- 

 ered the temperature by shutting the damper, and opening 

 the furnace door ; a singing from the aperture was soon ob- 

 servable, and when a coal was held before it, rapid combus- 

 tion ensued; nothing however was yet visible, but as the 

 temperature decreased, the steam became more and more 

 visible, the noise at the same time increasing, until finally the 

 roar was tremendous, and might have been heard at the 

 distance of half a mile. This was conclusive. I should 

 mention that, at the aperture, the iron was red hot. 



My belief is that water cannot be brought into contact with 

 iron heated to about 1200°, without a force equal to the max- 



