464 Intelligence and Miscellaneous A?- ticks. 



about one-third filled with CS 2 , steam from a flask with distilled 

 water be passed continuously by means of a tube which goes to the 

 bottom, the liquid (that is, the mixture of bisulphide and water) which 

 is traversed by aqueous vapour has the same temperature as the 

 mixed vapours. Both the liquid and the vapour indicated a tempe- 

 rature of 42°" 6, a temperature which of course varies with the 

 purity of the CS 2 used (boiling-temperature 46°" 6) and the barome- 

 tric height. The temperature once obtained is kept perfectly con- 

 stant as long as there is a small quantity of CS 2 in the cylinder. 

 The same temperature of 42° # 6 is maintained constantly in the liquid 

 and the vapour when the experiment is inverted, and water is poured 

 into the cylinder, and the latter heated by having bisulphide vapour 

 passed in. 



I made the same experiments with water and benzole, with water 

 and oil of cloves, and several other liquids, and in all cases with the 

 same result. When, for instance, aqueous vapour was passed into oil 

 of cloves, the mixed liquids and also the vapour showed very nearly 

 99°. More accurate numbers and a few remarks which naturally 

 arise out of them will be published subsequently. 



For the present it is my purpose to describe an experiment to 

 which I have been led by that above related ; for it elucidates in a 

 very clear manner, and one especially suited for lectures, that two 

 liquids which do not mix boil when together at a lower temperature 

 than the most volatile. As far as I am aware, the experiment has 

 not hitherto been described. 



If CS 2 boils when alone at 46°' 6, and CS 2 and water when together 

 at nearly 43°, it is clear that boiling must occur when both liquids are 

 heated separately to a temperature between 43° and 46°'6, about 45°, 

 and are then brought together. Experiment confirms this completely. 



Into a glass vessel about a foot in height and | foot in diameter 

 let water be brought whose temperature is not quite 46 0, 6, let a 

 test-tube about | inch in diameter be half filled with CS 2 and immersed 

 in the water until the temperature of the bisulphide has risen to 

 about 45°. 



If then the bisulphide be poured into the water, a brisk ebullition is 

 set up, which, with an adequate quantity of water, is maintained for 

 some time. If after a while the ebullition becomes weak or even 

 entirely ceases, stirring with a glass rod starts it again and keeps it 

 in fresh ebullition. By stirring, other particles of water are brought 

 into contact with the CS 2 , which have not yet been cooled down by 

 parting with the heat necessary for evaporation. 



Even when the entire mass has already been cooled below 42°, so- 

 litary bubbles rise, though there is no longer a continuous ebullition. 



The tension of the bisulphide is then only sufficient between the 

 bisulphide and the water, especially if the former does not cover 

 the entire base, but forms detached drops, to form a bubble (as 

 Quincke has also observed*), which, when it attains sufficient magni- 

 tude, can detach itself on shaking or stirring and ascends to the surface. 



Proper continuous boiling only sets in at a temperature of about 

 43°. — Poggendorff's Annalen, No. 7, 18/0. 



* Pogg. Ann. vol. cxxxix. p. 19. 



