EVIDENCE FOR THE EXISTENCE OF HYDRATES. 



The results plotted in fig. 17 for the nitrates present certain features 

 of special interest. The nitrates without water of crystallization, sodium, 

 ammonium, and potassium, give the smallest lowerings of the freezing-point. 

 Lithium nitrate, with 2 molecules of crystal water, gives considerably 

 greater lowering than the alkali nitrates. 



Concentration 

 FIG. 16. 



Calcium nitrate crystallizes with 4 molecules of water, and occupies a 

 position in the figure about midway between the alkali nitrates without 

 crystal water, and a number of nitrates each with 6 molecules of water of 

 crystallization. Manganese nitrate, of all the nitrates studied, gives smaller 

 lowerings than we should expect. We have repeated the experiments 



