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PROCEEDINGS OF THE AMERICAN ACADEMY. 



the heat capacity 1801 .5 of the added water. The slight decrease is 

 no larger than the possible experimental error; but it is probable that 

 the dilute solution really does suffer a small diminution of about this 

 order. 



Carrying out the same calculation for sodium hydroxide we find 

 the molecular heat capacity for NaOH.lOO H2O, 1780, and that for 

 NaOH.200 HoO to be 3580. The difference here again is slightly less 

 than the heat capacity of the added water, being 1800, instead of 

 1801 .5 — a difference of almost 0. 1 percent. 



Evidently solutions of strong bases and acids containing as much as 

 100 molecules of water (about half normal in equivalent concentra- 

 tion) are already so dilute that most of the added water is unaffected, — 

 or at least, such small changes as the water suffers must be balanced 

 by contrary eft'ects. Thus the specific heat of any more dilute solu- 

 tion may be calculated with considerable precision from the data con- 

 tained in this paper. 



Turning now to the comparison of the different substances, all in 

 solutions containing 100 molecules of water for each molecule of dis- 

 solved substance, we find other interesting and significant relations. 

 The following table presents the molecular heats of all the substances 

 for comparison: — 



TABLE XIV. 



The Molecular Heats of the Acid and Alkali Solutions of the Type 



:MX. 100 H.,0 



