connected with the Boiling of Liquids. 97 



Experiment 17. — In retort. 



o o 



Bath 208 Bisulphide 131. Distilling from surface, but not 



boiling. Nuclear speck in the 

 neck of the thermometer active. 



1.08 136. 



190 136. 



185 136. Nuclear point at the surface. 



181 134. Currents descending from the sur- 



face of the liquid in consequence 

 of a portion of the vapour being 

 condensed before it reached the 

 tube of the retort. 



177 131. Nuclear point above the surface. 



172 129. Distilling rapidly. 



The following experiments were made with a view to ascer- 

 tain how far the vapour above the liquid would become super- 

 heated. For this purpose two thermometers were passed into 

 a wide test-tube and so arranged that the bulb of one should dip 

 into the liquid, while the bulb of the other should be just above 

 its surface. Care was taken, as before, to have all the essential 

 parts of the apparatus chemically clean. 



Experiment 18. — Absolute alcohol boiling at 176°. 



Water-bath 208°. Alcohol 186° 188° 190°. 

 Vapour 168 174 176. 



During these observations there was a constant stream of 

 bubbles forming apparently a continuous inverted cone of vapour 

 ascending from a point on the stem of the immersed thermo- 

 meter. 



Bath 212 Alcohol 192. j A , burst °* ™P°p "?J £&?£$ 

 y r 176* ) force, and the alcohol fell to 190°; 



P ( the vapour remained the same. 



212 Alcohol 194. 1 Another explosive burst of vapour, 



Vapour 1/7. 1 and a fall of 2° in the liquid. 

 212 Alcohol 192. \ A burst of vapour, and fall of 2° in 



Vapour 176. f the liquid. 

 212 Alcohol 190.) „ . , - „ . nQ/ . 



Vapour 174 .[ Burst, and fall to 186°. 



The bulb of the thermometer was now exposed. The inverted 

 cone of bubbles ceased during the latter part of the observations. 

 Experiment 19. — Wood-spirit boiling at 154°. 



Bath 200° Spirit 158° 161 

 Vapour 148 151. 



There was a constant stream of bubbles from a nuclear point 

 on the bulb ; it ceased spontaneously after a few minutes. 



Bath 205 Spirit 167 

 Vapour 154. 

 Phil. Mag. S. 4. Vol. 50. No. 329. Aug. 1875. H 



