OF STEAi\r APJSTxri rnoi\r iiotltnt; salt solutions. 13 



Tlie flrrsks F, (r, niid IT wore smpportorl on stnnrls, and F rested on n 

 piece of nsl)estos r:i]'dl)o:ird, liavinii; u hole in tlie centre, so that only 

 tlie l)ott<^in miulit ])v heated by tlie direct flame. The stoppered 

 funnel' m a.iid 7/ : erved to aipply the flask.'. (J and }I with water and 

 acetic acid respectively, wheri necessary, without dismounting the 

 apparatus. The funnel iii further served, at the end of an experiment, 

 to restore the equilibrium of pressure between the outer air and the 

 inside of the flask G, thus preventing the salt solution from being- 

 sucked into the latter. The whole arrarjgeinent is exceedingly simple, 

 and can be fitted u]) by any one with materials found in every chemi- 

 cal laboratory. The three thermometers a, />, arid c had, finally, been 

 carefully verified, including tlie exposure correction for a and e. 



The salt solution, whose boiling point had been approximately 

 determined and known to be higher than that of the dilute acetic acid, 

 was introduced into the flask F by means of a long funnel, and the 

 inside of the neck of the flask then Aviped with a cloth, so that no 

 particle of the salt solutiori should be left adhering to it. Some 

 cotton-wool was loosely tied round the stem of the tliermometer h, 

 and below the bulb of the thermometer a ; this served as a very effec- 

 tive screen against splashing up of the solution on to the bulb of the 

 second thermometer a. A little cotton wool was also tied round the 

 stem of the thermometer a, and above its Indb ; this prevented any 

 water which might condense in the steam-issue tube s, from flowing 

 down the stem of this thermometer. The cork with its two thermo- 

 meters thus prepared was then fitted into the mouth of the flask F ; 

 this cork projected a little below that of the jacket, in order that there 

 miofht be no diance of steam condensino" within the neck of the flask. 

 The tubes u and t were covered with (^itton-wool in order to lessen 

 llie cooling action of the air on the acetic acid vapour and the steam 

 respectively. 



