1830.] On the Limits of Vaporization. 205 



Such are the principal reasons which have induced me to 

 believe in the existence of a limit to the tension of vapour. 

 If I am correct, then there are at least two causes, each of 

 which is sufficient to overcome and destroy vapour when re- 

 duced to a certain tension ; and both of which are acting 

 effectually with numerous substances upon the surface of the 

 earth, and retaining them in a state of perfect fixity. I have 

 given reasons for supposing that the two bodies named, which 

 boil at about 600 F., are perfectly fixed within limits of low 

 temperature which we can command ; and I have no doubt, 

 that nearly all the present recognized metals, the earths, car- 

 bon, and many of the metallic oxides, besides the greater 

 number of their compounds, are perfectly fixed bodies at com- 

 mon temperatures. The smell emitted by various metals when 

 rubbed may be objected to these conclusions, but the circum- 

 stances under which these odours are produced, are such as 

 not to leave any serious objections on my mind to the opinions 

 above advanced. 



I refrain from extending these views, as might easily be 

 done, to the atomic theory, being rather desirous that they 

 should first obtain the sanction or correction of scientific men. 

 I should have been glad to have quoted more experiments 

 upon the subject, and especially relative to such bodies as 

 acquire their fixed point at, or somewhat below common tem- 

 peratures. Captain Franklin has kindly undertaken to make 

 certain experiments for me in the cold regions to which he has 

 gone, and probably when he returns from his arduous under- 

 taking, he may have some contributions towards this subject. 



Royal Institution, May 4, 1826. 



On the Limits of Vaporisation*. 



I WAS induced some time since to put together a few remarks 

 and experiments on the existence of a limit to vaporization, 

 which were favoured with a place in the Philosophical Transac- 

 tions for the year 1826f. When the experiments there men- 

 tioned were published, I arranged some others bearing upon 

 the same subject, but which required great length of time for 



* Royal Institution Journal, 1830, i, 70. t See page 199. 



