438 Mr. C. Tomlinson on some Phenomena 



but sufficient to burn off any air, if air existed, still acts as a 

 nucleus. 



In my paper in the ' Proceedings ' the following experiment is 

 given : — 



" It is said that rough bodies are most favourable to the 

 liberation of vapour. The hot carbonic disulphide was touched 

 with a rat's-tail file, and it produced furious boiling. The file 

 was then held in the flame of a spirit-lamp, and while hot placed 

 in the upper part of the tube, so that it might cool down to 

 about the temperature of the liquid and yet be sheltered from 

 the air. On touching the surface of the disulphide with the end 

 of the file, there was no liberation of vapour ; and the file was 

 slowly passed to the bottom of the liquid, but still there was no 

 action. The file was now taken out and waved in the air; on 

 reinserting it into the liquid, there was a burst of vapour, arising 

 from some mote or speck of dust caught by the file from the air. 

 The file was quickly cleaned by the liquid, and it became inac- 

 tive as before. It was again taken out and waved in the air ; 

 and on once more putting it into the liquid, boiling set in again." 



But, according to M. Gernez, the file instead of catching nu- 

 clear particles caught air, which it reintroduced into the hot 

 liquid. He does not attempt to explain the following experi- 

 ment, although he refers to the paper containing it*. 



Wood-spirit, boiling at 140° F., contained in a test-tube, was 

 plunged into a flask of hot water. A clean glass rod that had 

 been exposed during an hour to the air of my garden was inac- 

 tive. It was drawn through the hand that had been made 

 slightly greasy with lard, and when reinserted it produced such 

 a burst of vapour as to turn out half the contents of the tube. 



A similar result was produced with ether and bisulphide of 

 carbon. 



Surely I am not exceeding the bounds of philosophical dis- 

 cretion in insisting that a theory of boiling that does not in- 

 clude within its geueralizing influence such results as the above 

 must be defective. 



I have endeavoured to showf that solids, in their action on 

 gaseous or vaporous solutions, admit of being arranged into four 

 classes : — (1) Vitreous bodies and certain metals which, in a ca- 

 tharized or chemically clean state, have no nuclear action, because 

 there is perfect adhesion between them and the solution. 

 (2) Bodies that are not wetted by the water of the solution, but 

 to which the gas or vapour can adhere. Such are fatty or olea- 

 ginous bodies and also resinous bodies; these act as nuclei. 



* "Reply to the Rev. Father Solaro in Les Mondes, Dec. 21, 1871,'* 

 Phil. Mag. March 1872. 



* Phil. Mag. April 1873. 



