Colloids on Radioactive Products in Solution. 



625 



Similar experiments with colloidal gold obtained by 

 Bredig's method have led to precisely the same results. 



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We may therefore conclude that the addition of a negative 

 colloid in small quantity makes the products deposited at the 

 cathode to diminish in amount and afterwards to disappear ; 

 that is to say, it produces the precipitation of colloids of 

 opposite signs. In the presence of still greater quantities of 

 negative colloids the positive products become negatively 

 charged, and they are then deposited at the anode : we have 

 thus before us a case of adsorption by a colloid being used 

 in great excess. 



