106 



Conductivities and Viscosities in Pure and in Mixed Solvents. 



TABLE 69. 



DISCUSSION OF RESULTS. 



From figures 7 and 8 the salts which produce the greatest increase in 

 velocity, and which have the largest temperature coefficients, are 

 magnesium chloride, calcium chloride, strontium chloride, barium chlo- 

 ride, magnesium nitrate, calcium nitrate, and strontium nitrate. All 

 of these salts crystallize with water of crystallization, varying from six 

 to two molecules each. Next come salts that do not have water of 

 crystallization, as sodium chloride, sodium nitrate, potassium chloride, 

 and potassium bromide. Along with these salts we have some that 

 have water of crystallization, as sodium bromide, calcium bromide, 

 lithium chloride, lithium bromide, lithium nitrate, and magnesium 

 sulphate, which seem to be exceptions in the light of the action of the 

 other salts that crystallize with water. 



Still more inexplicable are the curves for lithium sulphate, sodium 

 iodide, strontium bromide, lithium bromide, and potassium iodide, 

 since these curves are below the curve for pure water. 



Take figure 9. As the dilution is increased, salts such as magnesium 

 chloride show a marked decrease in velocity ; the salts with no water of 

 crystallization show a less decrease, while the apparent exceptions, such 

 as calcium bromide, strontium bromide, etc., show a marked increase 

 in velocity, most of their curves ending above the curve for water. 



Let us now consider the salts of any one metal (figures 7 and 8), e. g., 

 calcium. The chloride increases the velocity more than the nitrate, 

 the nitrate more than the bromide. With potassium and sodium the 

 chloride has more effect than the nitrate, the nitrate more than the 

 bromide, the bromide more than the iodide. Of the salts studied, 

 the sulphates have the least effect. There also seems to be a gen- 

 eral relation between the metals themselves, as magnesium, calcium, 



