connected with the Boiling of Liquids. 99 



Experiment 21. 



o 



Bath 1 10 Ether 

 Vapour 

 120 Ether 104. 



00. 1 

 90. J 



Ether 104. 1 -,-, . . , , , , c 



Vapour 94. | First bubble of va P our ' 

 124 Ether 110.) 



Vapour 94. j 

 140 Ether 114. 5 The vapour exploded and emptied the 



Vapour 96. / tube. 



Experiment 22. 



Bath 104 Ether 90. \ Stream of small bubbles from the ther- 

 Vapour 90. J mometer-bulb. 



124 vigour l 94' } Boilin S S eneral °ver the surface. 



134 Ether 102*. \ 

 The bath J Vapour 96. J 



gradually I 146 ( *5 ther ,^' \ The boiling ceased, 

 rose to ( (Vapour 120. J & 



lose to ) UQ Ether 122 



Vapour 108. J 



144 Ether 123. "I T1 i mmersed bulb became uncovered. 

 Vapour 110. J 



Experiment 23. — Water (distilled). 



Bath 2/0 Water 21 6. \ The bubbles arising from bulb, which had 



Vapour 168. J begun to rise earlier, now became larger. 

 270 Water 222. 1 A great upheaving of the Mater, and the 



Vapour 190. J temperature fell to 216°. 

 280 Water 222. \ Explosive burst of vapour, and water fell 



Vapour 196. J to 218°. 

 280 Water 222.1^... - „ . oico 



Vapour 1 96.) Ditto, fell to 216 V 



280 Do. Do. 



280 Water 220. 



Vapou 

 300 Water 



Vapour 202!} Do * 



Vapour 2ia } Boilin S became re & ular * 



It appears from these experiments that ether-vapour readily 

 becomes superheated from the column of vapour from the bath, as 

 already stated, but that it is difficult (at least in this form of the 

 experiment) to superheat a water- vapour. Mr. Hatcher says: — 

 " The tube in the water experiment must be surrounded by a 

 certain column of air heated by the oil or paraffine-bath ; but 

 the temperature (normal) of this vapour being high, it cannot 

 take much heat from the surrounding column of air, and appa- 

 rently its radiation of heat outwards for some time exceeds its 

 absorption of heat inwards. The vapour during a part of the 

 experiment is really underheated. 



In conclusion, I venture to think, from a survey of the details 



H * 



