vm, a, 2 Edding field: Gogo 139 



colors in the violet part of the spectrum and the finest particles 

 in the red. 



The most interesting feature is the formation of colloidal gold 

 solutions by means of a colloid (saponin) and in the presence 

 of an electrolyte (oxalic acid) , the two factors claimed by Zsig- 

 mondy to prevent its formation. 



SUMMARY 



Colloidal gold can be formed by — 



Gold chloride, fresh gogo, and oxalic acid, plus heat. 



Gold chloride and gogo (after standing), plus heat. 



Gold chloride, gogo, and calcium carbonate, plus heat. 



Gold chloride, gogo, and sodium carbonate, plus heat. 



Gold chloride, saponin solution, and sodium carbonate, plus heat. 



Gold chloride, saponin powder, and sodium carbonate, plus heat. 



Suspensions which have colors similar to those of colloidal gold 

 can be made by gold chloride and saponin alone plus heat, but 

 these settle quickly. 



