HYDRATES AND TEMPERATURE COEFFICIENTS OF CONDUCTIVITY. 



155 



table 101 have little or no water of crystallization, while those in the second 

 section of the table crystallize with large amounts of water. The water of 

 crystallization may be taken as roughly proportional to the hydrating power 

 of the substance. 



The substances in the first section of table 101 have much smaller coeffi- 

 cients of conductivity than those in the second section, even taking into 

 account the fact that those in the first part of the table are ternary electro- 

 lytes, while those in the second part are binary electrolytes. 



Another fact of equal importance is brought out by comparing the results 

 in the first part of the table with one another, and, similarly, those in the 

 second part of the table with one another. If the temperature coefficient of 

 conductivity is a function of the decrease in the complexity .of the hydrate 

 formed by the ion, with rise in temperature, then we should expect that those 

 substances which have equal hydrating power would have approximately the same 

 temperature coefficients of conductivity. 



TABLE 101. 



If we examine the above table we shall see that this is true. The sub- 

 stances in the first part of the table all have only very slight hydrating power, 

 as would be expected from the fact that they all crystallize without water. 

 Their temperature coefficients of conductivity are all of the same order of 

 magnitude and, indeed, are very nearly equal. 



The substances in the second part of the table all have very great hydrat- 

 ing power,, and all have a hydrating power of the same order of magnitude. 

 This would be expected, since nearly all of these substances crystallize with 

 6 molecules of water. There are a few compounds in this table calling for 



