PLANTS AND THEIR CULTURE. 107 



gain in bulk. At three years a single root has been 

 found to weigh between thirty and forty pounds ; 

 and, the larger the root, the less does it lose, in pro- 

 portion, by depreciation.* 



When the roots are taken up, they are suspended 

 under cover for ten or twelve days to dry. During 

 this time much of the water of vegetation is evapo- 

 rated ; the plant becomes soft, and is then subjected 

 to the heat of an oven from which bread has been 

 taken. After a second baking it comes out dry and 

 brittle ; and to disengage from it the earth, the small 

 fibres, and the outer skin of the root, it is lightly 

 threshed with a flail, after which it is fit for grinding. 



Of Woad. 



This plant, till 1756, was much employed, and fur- 

 nished the finest blue colour ; and, in the opinion of 

 some dyers, is even now very profitably united with 

 indigo, giving to the colour imparted by it more in- 

 tensity as well as duration. The maturity of the 

 leaves, which are the only useful part of the plant, is 

 announced by their drooping, and by the yellow col- 

 our which they take. At this signal they must be 

 stripped from their stems, housed, and left in mass 

 till, freed from the water of vegetation, they begin 

 to macerate by their own weight. They are then 

 to be washed and reduced to a paste ; after which a 

 fermentation takes place, and the fecula shows it- 

 self and forms a black crust, which is not to be bro- 

 ken, because necessary to prevent evaporation. 

 When the fermentation has subsided (which may 

 be known by the diminished stench), the mass is 

 pounded and formed into balls for use. The soil 

 and preparation indicated in the last article for mad- 

 der are most proper for woad. 



Of Saffron. 



This plant is culivated only for the stigmata of 

 the flowers, which give a yellow colour and are 



* In large roots this loss is 6-7ths, in small ones 7-8ths. 



