Taylor and Wells. — Preservation of Nets and Lines. 67 



Copper Oleate. There are many reasons for believing that 

 copper oleate will answer as well for the heavy duty set nets, 

 traps, etc., as for the lighter gear, the difference being in the 

 concentrations of copper oleate to be used. In the case of g^U 

 nets, a 10 to 12 per cent solution in gasoline, benzol, or carbon 

 tetrachloride with the addition of a little ordinary lubricating 

 automobile oil may be applied frequently; the heavy gear may be 

 treated with much more concentrated solutions, and not so often. 



So far as the writers are aware, copper oleate has never been 

 used before as a net preservative unless we may regard as the 

 same the soap-and-bluestone-treatment said to have been used 

 by the French sardine fishermen. At least it has never been 

 used in the way here recommended. Cunningham * mentioned 

 the process as used by the French, and in his trials included lines 

 treated with soap and bluestone, but his results were not at all 

 encouraging. On the basis of our work, a solution of copper 

 oleate, taking all factors into consideration seems best and most 

 promising of all and capable of being used to a great annual 

 saving by the fishing industry, and the writers submit this as the 

 principal constructive part of their work. 



Copper oleate can be had in the market as a commercial 

 article at about 22 cents per pound in barrel lots, containing up 

 to about 15 per cent copper. The two commercial samples ob- 

 tained and examined in this work did not appear entirely satis- 

 factory. They contain a high percentage of substances insoluble 

 in gasoline, benzol, etc., which appear to be by-product salts 

 that have not been removed. 



Accordingly, some work has been undertaken looking to- 

 ward the best methods of commercial manufacture of copper 

 oleate. Four principal methods are being studied, namely, (1) 

 precipitation of sodium oleate with copper sulphate, washing 

 and drying; (2) direct action of oleic acid on cupric oxide — the 

 ordinary black copper oxide; (3) the direct action of oleic acid 

 on copper acetate, wherein at 120° to 140° C. the acetic acid is 

 driven off ; and (4) direct solution at about 120° C. of copper 

 carbonate in oleic acid, or commercial red oil, whereby carbon 

 dioxide and water are driven off. At the present writing the 

 last named method seems most practicable and economical, and 



• Cunningham, J. T., The Chemistry of net-curing, Fish Trades Gazette 

 and Poultry, Game, and Rabbit Trades Chronicle. Vol. XX, Nos. 993 to 1009, 

 inclusive, June-September, 1902. London. 



