31 



24. J. W. McBain and H. E. Martin. (' Trans. Chein. Soc.', 1914, 105, 957.) 



Determinations of hydrolysis alkali by hydrogen electrode in sodium 

 hydroxide, sodium and potassium palmitates, potassium myristate to 

 acetate, with and witiiout excess of palmitic acid or alkali or sodium 

 chloride at various temperatures and concentrations and some commercial 

 soaps at 90°. 



25. J. W. McBain and T. R. Bolam. (' Trans. Chem. Soc.', 1918, 113, 825.) 



Determination of hydrolysis-alkali by rate of catalysis of nitrosotriace- 

 tonamine in sodium acetate and palmitate with and without added sodium 

 hydroxide and of potassium palmitate at various temperatures and 

 concentrations. 



IV. — Viscosity. 

 6, 7, 9, 10, above. 



26. A. Mayer, G. Schaeffeb and E. F. Tebboine. (' Compt. rend.', 1908, 

 146, 484.) 



Viscosity, appearance, sediments, dialysis of sodium oleate, from the 

 caproate to the stearate and oleate, with excess and deficiency of alkali. 

 Ultramicroscopic particles. 



27. F. BoTAZzi and Victoboff. (' Atti. R. Accad. Lincei.', 1910, 19, i., J359.) 



Surface tension, viscosity and appearance of a dialysed Marseilles 

 soap of unknown composition, with and without addition of alkali. 



28. F. D. Fabrow. (' Trans. Chem. Soc.', 1912, 101, 347.) 



Viscosity of sodium palmitate solutions at 70° in various concentrations 

 with and without additions of palmitic acid, sodium hydroxide, sodium 

 chloride or potassium chloride. 



V. — Optical. 



29. R. ZsiGMONDY and W. Bachmann. (' KoUoid. Zeitschr. , 1913, 11, 145.) 



Ultramicroscopic observations of the formation of curd in aqueous and 

 alcoholic solutions of sodium and potassium oleate, stearate and palmitate, 

 also solubilities and sediments and solidification temperatures. 



30. J. LiFscHiTZ and J. Bbandt. (' Kolloid-Zeitsch.', 1918, 22, 133.) 



Refractive index of sodium stearate, palmitate and oleate solutions 

 and of potassium palmitate in various concentrations at 70°. 



[Note. — The subject of soap manufacture will be dealt with by Prof. J. W. 

 McBain and Mr. Ernest Walls in the 4tli Report of the Committee. — W. C. McC.L.] 



ULTRA-MICROSCOPY: DEGREE OF DISPERSION- 

 MEASUREMENT WITH THE ULTRA MICROSCOPE. 



By George King, M.Sc., F.I.C. 



The physical and chemical phenomena observed in colloidal 

 solutions, depend upon four factors : the concentration of the disperse 

 phase, its size, sJiape, and internal structttre. A knowledge of these 

 factors is desirable in order that the phenomena observed in any 

 particular investigation may be interpreted in terms of the energy 

 distribution in the system. 



(a) Concentration of Disperse Phase. 



Hie concentration is often determined by the evaporation of the 

 dispersion medium — this method is satisfactory only in the absence 



