32 EXPERLMEIfTS WITU lONIZKD Ain. 



convection current often traversing many feet to meet it, and the results here, when 

 the active dust is at once introduced into the jet from ^vithin, are indistiiiiruishable 

 on the whole, provided the same color value (blue=l) be given to one of tlie colors. 

 The absolute volumes of charged air (liters/min.) evoking the coloi- may in different 

 experiments vaiy ovei' threefold. The reason for this, the absoi-ption" of the tube 

 t, figure 9, ^vill iippt-ar in the next chapter. 



