230 AMERICAN AGRICULTURE. 



scorch the madder over them. A person muse be in con- 

 stant attendance to watch and replenish the fires. The 

 heat will ascend through the whole, and in ten or twelve 

 hours it will all be sufficiently dried, which is known by its 

 becoming brittle like pipe-stems.*' 



Breaking and grinding. Immediately'after being dried, 

 the madder must be broken and ground immediately, or it 

 will gather dampness so as to prevent its grinding freely. 

 Any common grist-mill can grind madder properly ; and 

 when ground it is fit for use, and may be packed in barrels, 

 like flour, for market." 



Quantity per acre. Mr. Swift, of Ohio, has raised 2,000 

 barrels per acre in one crop of four years growth, at a nett 

 profit, including all charges of rent, labor, &c., of $200 per 

 acre. The roots of madder are also a good food for cattle, 

 but the expense and delay of producing it, will preclude its 

 use for that purpose in this country. 



WOAD (Isatis tinctoria, Fig. 50). 



Woad is largely used in this 

 country for dyeing, but generally, as 

 a base for blues, blacks and some other 

 colors, and for these it supplies the 

 place of indigo. There are several 

 varieties of woad, but the common 

 biennial plant is the only one culti- 

 vated. London says: 



" The soil for woad should be 

 deep and perfectly fresh, such as 

 those of the rich, mellow, loamy, and 

 deep vegetable kind. Where this 

 culture is carried to a considerable 

 degree of perfection, the deep, rich, 

 putrid, alluvial soils on the flat tracts 

 FIG. 50. extending upon the borders of the 



large rivers, are chiefly employed for the growth of this sort 

 of crop ; and it has been shown by repeated trials, that it 

 answers most perfectly when they are broken up for it im- 

 mediately from a state of sward. 



* This seems to be a simple way of accomplishing the object, and 

 within every one's reach ; but as carbonic acid gas is thus constantly 

 generated and closely confined, and by its gravity will occupy the 

 lower strata of air, the greatest caution will be necessary for the per- 

 son attending on the kiln drying, to prevent injury to himself 



