J_U J. ÖAKUKAI: DETEllMINATlOX Ui'^ THE TEMPÈRATUUE 



cing. My own experiments prove, moreover, tliat there exi.sts no 

 difference between the temperature of the boiling solution and that of 

 the steam issuing from it. 



The above smnmary should o-ive some idea of the vao'uenes., and 

 unsatisfactory character of tlie experimental evidence now existing 

 as re^'ards the temperature of tlie steam arising from a Ijoiling salt 

 solution. The following is a description of ]ny own experimented 

 methods, and the results oljtained by their means. 



Experhnenlal lYlelhods. 



For success in establishing the true temperature of the steam 

 escaping from boiling salt solutions, certain conditions must be 

 observed. 



1. The thermometer must be kept clear of all contact with the 

 s(jlution, even the smallest dro])s thrown up Ijy ebullition, as other- 

 wise it is evident that the experiment hjses all chiiui to accuracy. 



2. The elfect of the radiant cooling of the thermometer must either 

 be prevented, or rendered inappreciable in proportion to the heating 

 np by the stcimi. Ik^fore considering these alternative conditions, it 

 may be well to call attention to the familiar and striking evidence we 

 have that loss of heat by radiation from the bulb of the thermometer 

 does occur and cannot be neglected. Whenever distillation of water, 

 or any other liquid with no fixed matters dissolved in it, is going on, 

 the thermometer immersed in the vapour to record the " boiling 

 point " is seen to be always condensing some of the vapour, drops 

 falling from it into the boiling liquid. 



The former alternative seems hardly practicable, or, at least, has 

 proved to be impracticable under various conditions in my hands. 

 Tlie latter alternative, that of overpowering tiie 1(JSs (jf heat by 



