98 Mr. C. Tomlinson on some Phenomena 



A stream of vapour set out again from the thermometer. 



o o 



Bath 205 Spirit 170. 1 Explosive burst, and the spirit fell to 

 Vapour 158. j 168°. 

 208 Spirit 172. \ Explosive burst, and the spirit fell to 

 Vapour 156. J 162°. 



The thermometer-bulb now became uncovered. 



Mr. Hatcher remarks on the above : — " In the intervals be- 

 tween the great bursts of vapour there were frequent and some- 

 what regular formations of large bubbles of vapour in the liquid, 

 which seemed to heave up the whole surface at once. 



" The thermometer in the vapour acted as a condenser, drops 

 of condensed liquid constantly falling from the end of the bulb 

 into the heated liquid below ; but in no case did the fall of one 

 of these drops appear to be the cause of an explosion of vapour, 

 or of one of the large bubbles. 



"The thermometers were cleaned by being dipped into strong 

 sulphuric acid, washed in a stream of water, dipped into potash 

 solution, washed again, dipped into the liquid to be tested (this 

 was contained in a separate vessel), and then transferred as 

 quickly as possible to the test-tube in which the experiment was 

 to be made. Even with these precautions we seem to have had 

 nuclear points on the glass, although they ceased to act after a 

 time. 



" With respect to the apparent superheating of the vapour in 

 the last experiment, I should note that the test-tube with the 

 spirit stood vertically in a bowl of water, and was constantly sur- 

 rounded by the steam from the water. It is quite possible that 

 when the difference of normal temperature of the included vapour 

 and the external steam is great (as in the case of the wood-spirit) 

 some superheating of the included vapour may take place — not 

 rom the superheated liquid below so much as from the steam- 

 jacket enveloping the tube." 



The following are some further experiments on the super- 

 heating of the vapour over the surface of the superheated liquid. 



Experiment 20. — Ether and water-bath. 



Bath 115 Ether 96. \ u ' , 



Vapour 88 .} Burst of vapour. 



118 Ether 102. \ ^ .. , . f 



y c Qg V Explosive burst ot vapour. 



12G Ether lo5!"| 108 



1} 



Vapour 96./ V3 

 132 Ether 112. \ 



Vapour 101. J 

 140 Ether 116. \ 



Vapour 106. J 



During these observations distillation was going on rapidly 

 from the surface of the ether. 



