98 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



The Scotch formerly used tar and oil of turpeutiiie. The tar was first 

 boiled for oue hour, whereby it lost some of its " burulug" quality, 

 when an equal quantity of oil of turpentine was added, heated to a tem- 

 perature of IO40-I220 Fahr. The nets were then drawn through the 

 mixture. Instead of tar, thick turpentine was also used, and the su- 

 perfluous moisture was pressed out by letting the nets jjass through a 

 machine with two cylinders. When treated in this manner they kept 

 their natural color. 



In Xewfouudland pine, spruce, or birch bark is boiled until the liquor 

 has the required strength. It is then drawn oif and tar is added in the 

 ])roportion of one part tar to twenty parts of the mixture. 



Ill France the fishermen use a solution (2 to 4 per cent strong) of 

 alum and water, or sulpliureted copper or oxide of zinc. From England 

 we have received the suggestion to use alum dissolved in Avater and 

 buttermilk (2 ounces or G2 grains per gallon), in which the nets are laid 

 lor six hours. 



In Europe nets at present are generallj^ tanned. Especially has 

 catechu* {Terra japonica) found great favor during the last 30 years 

 for tanning nets. 



There are 3 kinds of catechu : + 



(1) Gambier catechu. — This is obtained by boiling the branches and 

 leaves of the gambier i)laut which grows in Farther India and on the 

 islands of the Indian Ocean. When it has evaporated it forms a clay- 

 colored mass, which is cut in inch cubes. W^hen these cubes are dry 

 they ore dark brown on the outside and light brown inside. Occasion- 

 ally nnich smaller cubes find their way into the market ; but these are 

 frequently adulterated with dried blood, flour, &c. 



(2) PaJm catechu. — This is obtained by boiling the fresh nuts of the 

 betel palm. There a,re two kinds, namely, the Kassu, which is formed 

 into round bricks, dark brown, 2 inches broad and one-half inch thick, 

 often covered on one side with rice-husks 5 and the Coiiry, which has a 

 yellowish brown color, and which when broken shows an earthy surface, 

 easily distinguishable from the Kassu, which shines on the broken sur- 

 face. Both tliese kinds are of an inferior quality. 



(3) Cutsch. — This is obtained from a species of acacia growing in India, 

 but now cultivated also in the West Indies. Pegu catechu comes in dark 

 brown lumps packed in leaves. It is heavier than water, has a bitter 

 taste, and is sai<l to contain 55 to 58 jier cent of tannin. r>eugal catechu 

 has a grayish brown color, and when broken shows shining streaks or 

 layers. It generally comes in lumps of 1 to 3 inches in diameter. It 

 contains about 50 per cent of tannin. 



Purified catechu comes in cakes weighing about one i^ound each. It 

 is generally adulterated. 



The characteristics of good catechu are that it has a brown color, and 



* It became known in Europe in the sixteenth century and was used in mi-dicinc. 

 t Danish Fislvoritidondo, 1885. 



