10 



BULLETIN 706, U. S. DEPARTMENT OF AGRICULTURE. 



contains usually from 22 to 24 per cent of tannin and is sold on the 

 basis of its strength, has increased materially in the past few years. 

 For 42 extract the quoted price a pound was: In 1914, about 3| 

 cents; in 1915, from 3| to 9 cerfts; in 1916, from 5J to 10 cents; in 

 1917, from 4J to 5 cents ; in 1918, from 4J to 5 cents ; and in August, 

 1920, from 7 to 8 cents. 



A pound of extract contains approximately the same amount of 

 tannin as a pound of properly gathered and cured leaf. In making 

 the extract the tannin is extracted with large quantities of water 

 which must be evaporated in expensive copper pans under skilled 

 supervision and at some expense for fuel. When the extract is to be 

 used, as much or more water than was evaporated in making it is 

 added to secure a tanning or dyeing solution of the desired strength. 

 The consumer, however, often prefers to use the extract, rather than 

 to make his cwn liquor from the leaf. 



DISPOSAL OF EXTRACTED MATERIAL. 



So far as can be learned, no really satisfactory method of disposing 

 of the extracted leaves is in general use. The material is placed in 

 large piles or ricks, or taken to fill in waste places. A small quantity 

 is used on farm land as a top-dressing to be plowed under. Analyses 

 of the commercially extracted material given in Table 5 show its 

 fertilizing value. 



* 



TABLE 5. Fertilizing value of commercially extracted sumac leaves and leaf 



stens and stalks. 



Examination of a number of unextracted sumac samples gave: 

 Ash, 4 to 7.5 per cent; potassium oxid, 1.18 to 2.15 per cent. Ttie 

 ash of these samples contained from 25 to 30 per cent of potassium 

 oxid. 



Comparison of the percentage of potassium oxid (K 2 O) in the 

 original material and in the water extract, as obtained for the tannin 

 analysis, shows that although the unextracted sumac contains rather 

 high percentages of potassium oxid, this is almost entirely removed 

 on extraction. These experiments were made on finely ground su- 



