SUMMARY AND CONCLUSIONS. 145 



8. It has been pointed out that the hydrates formed in aqueous solu- 

 tions are unstable, especially at higher temperatures. They are, in general, 

 broken down at the boiling-points of the solutions, all of the water escaping 

 except that which is held in combination by the salt as water of crystalliza- 

 tion. 



9. As the result of this work as a whole, we must conclude that both mole- 

 cules and ions have the power to combine with water in aqueous solutions 

 and form hydrates. 



10. The new hydrate theory differs fundamentally from the old, in that, 

 according to the former, we have a series of hydrates formed by the dissolved 

 substance, having all possible compositions up to a given maximum the 

 composition depending on the concentration, as we should expect from the 

 law of mass action. 



11. The bearing of this work on the general theory of solutions is obvious. 

 The fact that a part of the water is combined with the dissolved substance 

 and is not acting as solvent, must be taken into account in dealing with all 

 solutions and especially with concentrated ones. This accounts, in large 

 part, for the abnormal behavior of concentrated solutions, and is, doubtless, 

 an important factor in the apparent failure of the gas laws to apply to 

 such solutions. When this is taken into account, together with such other 

 factors as appear in Van der Waals's equation for gases, it will probably be 

 shown that the gas laws apply to the osmotic pressures of concentrated 

 solutions, measured under comparable conditions with gases, as well as to 

 concentrated gases. 



