PRESERVATION OF I'lSH NETS. 



29 



8. Coal tar and green oil niix<Hl. — The net was steeped in the mixture, then 

 passed through a wringing machine, and hung up to dry. 



9. Cutoh anil green oil. — Tlie net was steeped sevei'al days in cutch, one-half 

 pound to one-half gallon of water, tlien dried and i)ut into green oil, then passed 

 through a wringing machine and hung up to dry. 



10. Green t>il alone. — The net was simply saturated with green oil, passed 

 through a wringer, and hung up to dry. 



11. Cutch and Stockholm tar, mixed (one-half pound cutch boiled in one-half 

 gallon of water, and one-half pint Stockholm tar stirred into the hot solution), — •' 

 The net dipi)ed into the mixture, squeezed out. and dried. 



12. Cutch, Stockholm tar, and green oil. — The net was steeped three days in 

 cutch, one-half i)()und to one-half gallon of water, then dried and soaked in 

 Stockholm tar warmed, with a little turpentine added. As the net was very 

 hard and sticky, it was soaked with green oil and passed through the wringing 

 machine. 



13. Cutch and linseed oil. — The net was steeped in cutch (one-half pound 

 to one-half gallon of water) for three days, dried, and then dipped in boiled oil, 

 with driers added. After some weeks it was dipped again in cutch and dried. 



14. Soap ami copper sulphate (one-half pound soap boiled in one-half gallon of 

 water). — The net soaked in this and then put into a solution of copper sulphate, 

 one-half pound to one-half gallon of water. 



15. Soap, copper sulphate and linseed oil. — The net, prepared as in 14, was 

 saturated with boiled oil, with driers added, and hung up to dry. 



The pieces were all cut from the same mackerel net, 24| ro^YS to 

 the yard. 12-ply, and the following table shows the results of testing : 



Mode of cure. 



Strenirth after 



2 months in 



water. 



1. Cutch only, two dips and steeped 



2. Glue and cutoh, one dip in glue, two in cutch 



3. Cutch, ghie, and biehromate of potash , 



4. Cutch and copper sulphate 



5. Cutch and coal tar, tarred first 



6. Cutch and coal tar, mixed 



7. Cutch, tar, and green oil, passed direct from the 



cutch into the tar 



8. Coal tar and green oil, mLxed 



9. Cutch and green oil 



10. Green oil alone 



11. Cutch and Stockholm tar mixed 



12. Cutch, Stockholm tar, and green oil 



13. Cutch and linseed oil , 



14. Soap and copper sulphate , 



15. Soap, copper sulphate , and linseed oil. . , 



Lbs. 

 6 



18 



ozs. 

 6 



It is evident that Cunningham did not carry his tests far enough 

 to give decisive indications. In spite of this insufficiency, it is plain 

 that those methods are good which depend on tar or oil as a protec- 

 tive covering, where these substances really cover, but when they are 

 broken up into tiny particles or applied to a wet net, as in Nos. 6, 7, 

 and 11, little protection is given. 



SHKINKAGE CAUSED BY PRESEE^^NG. 



Cunningham also kept a record of the shrinkage caused by the 

 various methods of curing nets. As stated above, the nets were 24| 

 rows per yard before treatment. After treatment they varied ac- 

 cording to the following list. (Of course, the greater the number 

 of rows there are the more the shrinkage that has taken place.) 



