302 CHYMISTRT APPLIED TO AGRICtlLTTDRB.^ 



ARTICLE III. 



The Extraction of Indigo from Woad. 



Before the discovery of indigo, the isatis tinctoria was 

 cultivated for the manufacture of vpoad cakes in nearly 

 all parts of Europe : the blue color obtained from this 

 plant was the most durable one known, and the commerce 

 in woad was immense. 



The neighbourhood of Toulouse, and particularly Lara- 

 guais, furnished an enormous quantity of woad, and the 

 cakes prepared there were everywhere considered of the 

 best quality : this section of the country became so rich, 

 that it was called the pays de cocagne, from the name of 

 its manufacture ; and this epithet has passed into a proverb,, 

 aad is used to designate a very rich and fertile country. 



Two hundred thousand packages of cakes were ex- 

 ported every year by the port of Bordeaux alone : so great 

 was the want of this commodity amongst foreign nations, 

 that, during the wars we were obliged to sustain, it was 

 always agreed that the commerce in it should be free and 

 protected, and that foreign unarmed vessels should be 

 allowed to come into our ports to obtain it. 



The finest establishments at Toulouse have been found- 

 ed by the manufacturers of woad cakes ; when Charles V. 

 wished to secure the ransom of Francis I., who was a 

 prisoner in Spain, he required that the rich Beruni, a 

 manufacturer of this article, should become surety for it. 



The indigo, which is an extract from a plant of the 

 same name, first made its appearance in Europe early in 

 the seventeenth century; and the injury which the culti- 

 vation of woad would receive from it, was foreseen from 

 the first moment of its introduction. An equal weight 

 of the pure coloring principle of indigo contains about 

 165 times more coloring matter than the woad cakes do. * 

 Thus 15 lbs. of good indigo, such as is usually employed in 

 dying, are equal, in point of coloring matter, to 2625 lbs. 

 of the woad cakes. From this, some judgment may be 

 formed of the difficulty of producing a deep dye with the 

 woad alone; for, besides the inconvenience of managing 



* This calculation is founded upon the supposition that 100 lbs. of 

 woad leaves yield 3 oz. of indigo ; for the cakes, which contain all the 

 ifldigo of the plant, represent only J of the weight of leaves employed 

 ifa their manufacture. 



