Force to Latent Heat fyc. of Electrolytes. 



167 



temperature during the short period of an experiment. The 

 thermometer was capable of measuring to *01 of a Centigrade 

 degree. 



The lower compartment of the large tube and the bore of 

 the stopcock were perfectly filled with the lightest of the two 

 liquids at exactly the proper temperature ; if this lower space 

 was not sufficiently large a glass bulb was previously fixed 

 water-tight on the lower end of the tube. The upper com- 

 partment and a part of the narrow tube was now filled with 

 the heavier liquid, and the apparatus immersed in the bath. 

 When the whole had acquired the same temperature, the tap 

 was slightly opened for an instant and closed again, the index 

 adjusted to the level of the meniscus, the tap then fully opened, 

 the apparatus occasionally inverted, the liquids allowed to mix, 

 and the changes of total volume of the liquids and the tempe- 

 ratures noted at stated intervals of time until all change of 

 volume ceased. The apparatus and method are suitable for 

 making accurate measurements. The following are the results 

 obtained : — 



Table II. 



Change of Volume of Electrolytes by Dilution. 



Substance. 



Solution. 



Water. 



Change of Volume. 



Acetic acid... 

 KHO 



11-0 c.c. 

 11-0 , 

 110 , 

 11-0 , 



iro , 



110 , 

 110 , 

 10-5 , 

 10-5 , 



of concentd. Acid. 

 , satd. solution. 



i 



2 » " 



c.c. 

 10-5 

 10-5 

 10-5 

 10-5 

 105 

 105 

 360 



no 



110 



Contraction 166 per cent. 

 •93 „ 

 •61 „ 

 •58 



•293 „ 

 •187 „ 

 •12 

 „ extremely small. 



Expansion "0587 per cent. 



Am 2 S0 4 



Sr2NOo 



Mgso; 



Na Acetate... 

 AmCl 



AmHO 



With the solution of aqueous ammonia, if sufficiently dilute, 

 contraction occurred, but when strong, expansion took place ; 

 probably similar results would be obtained with dilute hydro- 

 cyanic acid. Some practical mechanical application of liquid 

 expansion by mixture might perhaps be made to produce 

 hydrostatic pressure. 



The above results, together with those previously obtained 

 by other investigators (see references already given), show 

 that in 18 out of the 20 mixtures of liquids employed in this 

 research, contraction of total volume of the two electrolytes 

 occurred during the act of mixing. This large proportion of 

 cases of contraction indicates the existence of a great number 

 of instances of the same kind, and that probably nearly all 



