10 



BULLETIN 466, TJ. S. DEPARTMENT OF AGRICULTURE. 



standing for the basic solution and 0.79 for the normal lead, indicate 

 what may happen when the basicity of the acetate is changed. 

 Browne has called attention to the fact that the basicity of the lead 

 acetate affects the polarization and also that by digestion of varying 

 amounts of neutral lead acetate and litharge at least three well-defined 

 subacetates may be prepared. 1 Changes in treatment as to tempera- 

 ture and length of time of heating and also quantity of the two ingre- 

 dients may form any one of these or a mixture of two. 



An attempt was made to prepare solutions of these different basic 

 lead acetates by varying the amount of lead oxid and the manner of 

 solution as shown in Table VII. After the solutions were made up 

 they were diluted to the same Brix as Winton's solution and a layer 

 of heavy oil placed on top. The alkalinity and amount of lead 

 were determined in each. 



Table VII. — Effect of method of preparation on basicity of lead acetate solution. 



Solu- 

 tion No. 



Lead 



acetate. 



Grams. 

 37.9 

 37.9 

 75.8 



Home's 

 43.0 

 37.9 

 75.8 



Neutral 



Litharge. 



Grams. 

 22.3 

 44.6 

 22.3 



Water. 



Cc. 



330 

 330 

 330 



Solution treatment. 



Stood a week; shaken. 



Solution lost 



Stood a week; shaken. 



dry lead subacetate dissolved. 



13.0 I 1,000 I Boiled half hour. 



22.3 330 Do 



22.3 I 330 | Do 



lead acetate, saturated solution. 

 I 1 I 



Brix 

 reading. 



Degrees. 

 15.60 



15.80 

 15.60 

 16.20 



15.77 

 15.87 

 15.87 



Nitric 

 acid. 



Cc NjW 

 acid per 

 10 cc. 

 30.15 



18. £5 

 26. 25 

 26.00 

 27.50 

 19.60 

 2.00 



Lead. 



Per cent. 

 5.70 



5.59 

 5.82 

 5.68 

 5.80 

 5.73 

 5.44 



Grams per 

 2.6 cc. 

 0. 1426 



.1398 

 .1454 

 .1421 

 .1449 

 .1433 

 .1359 



The lead numbers of six samples of maple sirup were determined, 

 using these seven solutions. The results appear in Table VIII. 



Table VIII. — Effect of basicity of lead acetate solutions upon the lead number. 



Sample No. 



Lead solution number. 



1 



3 



4 



5 



6 



7 



8 



1 



1.49 

 1.74 

 1.79 

 1.61 

 2.00 

 1.86 



1.13 

 1.34 

 1.41 

 1.29 

 1.47 

 1.40 



1.29 

 1.42 

 1.57 

 1.37 

 1.64 

 1.58 



1.31 

 1.51 

 1.56 

 1.46 

 1.70 

 1.63 



1.40 

 1.62 

 1.72 

 1.55 

 1.80 

 1.78 



1.13 

 1.27 

 1.39 

 1.26 

 1.41 

 1.47 



0.29 



2 



.36 



3 



.36 



4 



.34 



5 



.39 



6 



.37 









1.75 



1.34 



1.48 



1.53 



1.64 



1.32 



.35 







Solution 4, the one usually employed, consisted of 3 parts of lead 

 acetate to 2 parts of lead oxid. Solution 5 was carefully prepared 

 by a method that should give this acetate. The results obtained 

 from solutions 4 and 5 agree fairly well, the difference between the 

 averages being only 0.05. Solutions 1 and 6 give results that are 



i U. S. Dept. Agr., Bur. Chem. Bui. 122, p. 223. 



