312 CHYMISTRY APPLIED TO AGRICULTURE/ 



If it should be ascertained that this manufacture would 

 be advantageous in peaceful times, it certainly must be re- 

 garded as of great importance at those periods, when a 

 maritime war, by increasing the difficulty of procuring 

 foreign indigo, shall cause the price of it in commerce to 

 be greatly enhanced. Besides, if good king Henry IV. 

 was willing to pronounce penalty of death upon the im- 

 porters of indigo, in order that he might preserve to agri- 

 culture the manufacture of woad cakes, why should not 

 government prohibit the importation of the same article as 

 soon as the manufacture of it from woad is established ? 

 France would, by such a course, be endowed with a pro- 

 duct of the value of at least 20,000,000 : she would be 

 placed above the chances of war, would retain within her- 

 self an immense sum which passes into foreign hands, and 

 would furnish employment to the numerous population of 

 the fields. 



But let us see if, in the actual state of things, the manu- 

 facture of woad indigo can compete with the importation 

 of it. 



An acre of land (old Paris measure) produces at the 

 various cuttings 7^ tons of woad leaves. At the lowest 

 calculation, the product of an acre in leaves, especially 

 in the south, may be fixed at 7^ tons, and that of the in- 

 digo which they will yield, at three ounces per hundred 

 weight, will make nearly 28 lbs. of indigo per acre. 



The value of good indigo may be estimated at nine 

 francs (a franc being about eighteen or nineteen cents), 

 and this will make the value of the indigo from an acre of 

 land to be 252 francs. Let us now compare this with the 

 value of wheat raised upon the same land : the quantity 

 of wheat may be estimated at about 12 hectolitres ( = 34 

 bushels), and the price at eighteen francs; this will give 

 215 francs per acre. We will now calculate and compare 

 the expense attendant upon the cultivation of each plant. 



The preparation of the ground by tillage and manures 

 is the same for the seeds of both plants, but the expense 

 of cultivation and of hand-labor differ essentially. 



Weeding by the hand is sufficient for wheat, and the 

 expense of this is very trifling, whilst the same operation 

 when performed upon woad, to which it is much more 

 necessary, must be done with instruments which will 

 loosen the earth, and root out all the noxious herbs : the 

 expense of this cannot be estimated at less than twenty- 

 five francs. 



