BULLETIN OF THE UNITED STATES FISH COMMISSION. 103 



as also for takiui;' the nets out, the main point being that the solution 

 should get on the nets as hot as possible, and it would take too long 

 to wait till it has cooled off' sufficiently to use the hands. When the 

 process is finished, the nets are laid in a pile and covered up. Thus 

 they should be left to lie for a few hours. If the work is finished in the 

 evening they may remain lying over night. 



When nets are to be stored away all the lines should be kex)t se^iarate 

 from the nets. Before being laid away the nets should be soaked in 

 fresh water for twenty-four hours, so that all the salt may come out, for 

 salt will attract moisture. While drying they should be taken in everj^ 

 evening and during raiuj' weather. The best place to keep them is an 

 airy loft, where they are either hung up or piled up loosely. In the 

 latter case they should be aired every now and then, especially iu damj) 

 weather. 



In conclusion we will mention the following methods of preserving 

 nets or of employing catechu: 



To 1 quart of water take ^ pound of catechu ; in this solution, when 

 cooled off, the nets are laid over night. Before they are dried they are 

 well rinsed iu fresh water, which makes them softer than if they had 

 not been rinsed. Occasionally J ounce of sulphureted oxide of copper 

 is added to each quart of water. In some places a solution of 4^ iiounds 

 of catechu and 3 gallons of oak bark is used for 20 gallons of water. 



In Sweden they use, especially for cotton nets, a decoction of birch 

 bark, cut fine. If the bark is fresh it can be boiled immediately, while 

 old and dry bark is first soaked for three days. To 26 gallons of water 

 take 4 gallons of bark and about 13 pounds of soda, and boil the whole 

 for three or four hours. When the solution has cooled oft' it is poured 

 over the nets, which are laid in vats or barrels. When they have been 

 thoroughly penetrated by the solution they are dried. If the nets are 

 iu use they should be tanned every month. For new nets, the first 

 time, 2i pounds of catechu are used to 26 gallons of water. 



In mau}^ places bark is used instead of catechu, and in Norway bark 

 is used almost exclusively. All kinds of bark are used ; the tannin 

 and the coloring matter may be extracted fiom it both by boiling and by 

 cold water. In England oak bark is generally used, and in Norway 

 birch bark. As a rule, the weight of the nets and of the bark used 

 should be the same, and 30 gallons water should be used to 40 pounds 

 of bark. If the bark is boiled, a little less may be used. Tanning in a 

 boiling solution will make the nets more durable, and will take less 

 time, as the nets need not be left in the solution more than 24 hours. 

 In this case they should be well covered. Owing to lack of suitable 

 vats for large nets, cold tanning is generally employed, and the process 

 is carried on either in the tanning A^at itself or in a special vat, some- 

 times even in a l»oat. The soaking of the bark, so as to give the solu- 

 tion the necessary strength, takes 4 or 5 days in summer, and about 14 

 days iu winter. When the solution is ready, tanning begins, the nets 



