23 



found best to defer harvesting after the second year. But we 

 have found that there is no material difference in the tannin 

 contents of the full grown root whether the plant is resting, 

 blooming or seeding. 



Marketing. As has been stated above, the canaigie root, 

 while an excellent keeper wh( n kept very dry, spoils readily 

 when kept in mass. It cannot therefore be shipped green to 

 any great distance, but must for distance shipments be either 

 dried or converted into extract. 



Drying is costly and laborious, and after all of somewhat 

 uncertain result on the large 6cale. Tannin is a very easily 

 decomposable substance ; drying at a high temperature will in- 

 jure it as well as when, at too low a temperature the drying 

 progresses too slowly and permits fermentation to start up. 

 Even small roots cannot be dried whole without serious 

 deterioration ; it is absolutely necessary to slice them, very 

 much as beets are sliced for sugar making. But when 

 machinery is once procured for slicing, it seems better to go a 

 step further and end all fear of deterioration by preparing the 

 extract, which will keep indefinitely. 



The cost af a factory plant for preparing the extract need 

 not be large, but it must be managed by competent hands. 



According to the data obtained by the Arizona station, 

 agreeing well with the averages obtained by us, three tons of 

 green roots will make one of dried, or one-half ton of 

 extract ; of six tons of green root will yield one ton of extract, 

 averaging from 60 to 65 per cent, of tannin, and, therefore very 

 well capable of shipment to a distance so far as value is con- 

 cerned. 



Comparing the canaigre with other tanning materials given 

 in the table, it will be seen that the bark of the black wattle and 

 golden wattle exceed the root in tannin contents. The question 

 then arises whether, supposing the two materials to be of equal 

 quality for tannin purposes, it will be more profitable to grow 

 canaigre than the wattles. An approximate comparative 

 estimate for the crops will therefore be of interest. 



Here the time element comes in as an essential factor. It 

 takes eight or ten years to mature a wattle plantation ; the 

 yield of bark per acre is for the first eight years (for the black 

 wattle), estimated at about twelve tons, besides possibly 100 

 cords of wood, available for Crewood. This estimate is based 

 upon the planting of 400 trees per acre ; close planting being 

 desirable in order to secure long trunks. The bark is worth 



