414 



U. S. BUEEAU OF FISHERIES 



months. The quercitron-ammoniacal copper sulphate method (L), 

 and the proprietary waterproofing (JJ) seemed to be of httle value 

 as preservatives. Samples treated with these materials were com- 

 pletely rotten in four months, while the untreated white line (A) 

 lasted for three months. The quercitron method did not show as 

 satisfactory, results during this test at Beaufort as it did during the 

 1922 test. Azulmic acid (MM) showed no preservative qualities. 



SUMMARY OP RESULTS AT BEAUFORT 



1. In the preservation of tensile strength of cotton lines the ma- 

 terials tested may be divided into five groups, according to their 

 value, as follows: (1) The copper oleate-coal tar mixture, (2) coal 

 tar, copper oleate, and the copper oleate-boiled linseed oil combina- 



50 



45 



40 



z 35 



z 30 



X 



t5 25 



z 



^20 



- 15 



12 3 4 5 6 



NUMBER OF MONTHS EXPOSED 



Fig. 1. — Tensile strength of cotton line at Beaufort, N. C. 



tion, (3) copper oleate-raw linseed oil, copper oleate-paraffin com- 

 binations, and the proprietary wood preservative, (4) the quercitron- 

 ammoniacal copper sulphate treatment and the proprietary water- 

 proofing, and (5) azulmic acid. 



2. The quercitron-ammoniacal copper sulphate method was less 

 effective as a preservative in 1923 than it was during the previous 

 year's tests. This may be due to a difference in water conditions. 



3. The addition of hnseed oil to copper oleate appeared to de- 

 crease the solubility of the latter to a slight degree. However, this 

 combination was less resistant to fouling by marine growth than 

 copper oleate alone. 



SERIES EXPOSED IN SEA WATER AT BOOTIIBAY HARBOR, ME. 



PURPOSE OF THE EXPERIMENT 



Beginning June 19 and extending to December 19, 1923, two 

 series of cotton lines preserved with various materials were exposed 

 in sea water at Bootiibay Harbor, Me. Some question had arisen 



