CHEMICAL CONTROL OF DIPPING T.\NKS. 



III. Private Tanks. 



139 



(a) Tanks using an arsenical dip containing coal tar deriva- 

 tives in addition: — 



Dates of 

 Sampling. 



Amt. of 



Arsenite. 



(Arsenious 



Oxide). 



Total . 

 Arsenic. 



Percentage 



of 

 Oxidation. 



Remarks. 



1921. percent. percent. percent. 



July 20 0-073 0104 29-8 100 head dipped fortnightly. 



July 27 0-141 0-158 10-8 Fresh raw dip added. 



Sept. 16. 0094 0-141 33-2 



Nov. 8. 0090 0-146 38-4 



1921. 



July 18. 

 Aug. 31. 



per cen*:. per cent. per cent. 



0-157 

 0155 



0-160 

 0-158 



1 -9 150 head dipped weekly 

 1-9 



