1 06 ADVENTURES IN RADIOISOTOPE RESEARCH 



sample, 32.26 scale divisions per min (calculated for complete ex- 

 change, 32.43 scale divisions per min) ; standard sample, 64.86 scale 

 fli visions per min. 



In a further experiment the standard substance used was the residue 

 obtained by evaporating the mother liquor from the precipitated for- 

 mate. The accuracy of the experiment was sufficient to establish the 

 uniform distribution of the activity between formate and acetate. In this 

 experiment 1.00 gm of formate and 1.30 gm of acetate were dissolved in 

 20 ml of w^ater. 



Measurement with 0.134 gm of each substance : Experimental sub- 

 stance, 22.38 scale divisions per min ; standard 20.61 scale divisions 

 per min. 



3. Plumbous Acetate (Active) and Plumbic Acetate in Glacial Acetic Acid 



Plumbous acetate (1.60 gm) was dissolved in a little glacial acetic acid 

 and the whole was poured into 50 ml of hot glacial acetic acid containing 

 2.20 gm of dissolved crystalline plumbic acetate^. The solution, after 

 clarifying by filtration, was kept for 10 min at 80°C, diluted with water 

 to four times the volume and boiled. Measurements were made on the 

 deposited lead peroxide after washing with dilute acetic acid and al- 

 cohol and drying. The residue obtained by evaporating an aliquot 

 part of the filtrate was used as standard. 



Measurements were made with 0.136 gm of each substance : Experi- 

 mental sample, 20.00 scale divisions per min; standard, 21.95 scale 

 divisions per min. 



4. Plumbic Acetate (Active) and Plumbous Acetate in Glacial Acetic Acid 



The active plumbic acetate was prepared by the addition of an active 

 sample of red lead, obtained by the oxidation of lead monoxide^, to 

 glacial acetic acid. A portion of the beautifully crystalline acetate was 

 used as a standard. Plumbic acetate (1.72 gm) and 1.48 gm of plumbous 

 acetate (Kahlbaum) were dissolved in 15 gm of hot glacial acetic acid 

 to an almost completely clear solution. The plumbic salt which crystallized 

 on cooling the solution for some time was washed with cold glacial ace- 

 tic acid, and dried by pressing and in a partial vacuum. 



Measurements on 0.400 gm of each substance : Experimental sample, 

 1 .29 scale divisions per min (calculated for the case of complete exchange, 

 1.43 scale divisions per min) ; standard, 2.86 scale divisions per min. 



1 A. Hutchinson and W. Pollard, Soc 63, 1136 (1S93) : Ibid. 69, 212 (189G). 

 See also A. Colson, C. R. Acad. Sci, Paris 136, 670, S91, 1666 (1903). 

 -L. Vanino, Praparative Chemie 1, 488 (1913). 



