president's addkess. 15 



to him by Miss Hornblower on the death of Jonathan Hornblower 

 in 1815. There are about 60 letters of J. Hornblower and 50 of 

 Davies Q-ilbert. The first letter, dated March 25th, 1790, makes 

 an appointment to meet Mr. Davies Gilbert at Tincroft, and the 

 following note made by Davies Gilbert, in 1815, when recording 

 Hornblower's death, alludes to his appointment. 



"Feb. 33rd, 1815. On this day died Mr. Jonathan 

 Hornblower, of Penryn, inventor of the steam engine with two 

 cylinders." 



"I became acquainted with this gentleman in 1790, when I 

 met him at Tincroft mine in Illogan to talk about purchasing 

 a model steam engine for Oxford ; and for several years after I 

 frequently assisted him in making experiments, and especially 

 in calculations." 



' ' I most earnestly recommended him to try the condensation 

 of strong steam raised by a quick fire." 



''I founded my opinion of strong steam on the principle 

 that about 1000 thermometrical degrees of heat being rendered 

 latent by the conversion of water into steam, it seemed to me 

 very improbable that the capacity of steam could be so great as 

 to require a 1000 degrees more to double its elasticity. These 

 recommendations were made about 1793." 



"In 1815, Mr. Woolf is actually performing 38 millions by 

 this means, when 20 years ago the average duty of engines in 

 Cornwall was about 14 millions." 



"I first got acquainted with Mr. Jonathan Hornblower in 

 consequence of his having applied the expansive power of steam 

 by the application of a second cylinder about twice the capacity 

 of the first. He constructed a working model, which I wished 

 to have purchased for a lecturer at Oxford. I met Mr. H. at a 

 mine in Camborne, where he had put up a large engine on this 

 principle, and he was very much surprised when I gave him the 

 power of his second cylinder as compared with the first, supposing 

 the vacuum perfect and friction evanescent." 



I quote the original description of this engine from a printed 

 bill got ready to be introduced into the House of Commons to 

 secure an extension of his patent for this engine, 1792. Original 

 patent dated 13th July, 21 Geo. iir, or 1780. 



