264? Notices respecting New BooJcs, 



they should fall immediately after the young plants show themselves 

 above ground, in order that they may be invigorated, and enabled 

 to resist the attacks of the numerous insects to which they are, at 

 this period of their growth, exposed. From this time little rain is 

 required, except immediately after the branches have been cut ; at 

 these periods a shower is of great service, enabling the plants to send 

 out new and vigorous shoots. A wet chmate indeed is not at all 

 suited to the cultivation of the Indigo. It is true that the plant may 

 grow luxuriantly, but the juices are watery, and the produce obtained 

 is small in quantity, and inferior in quality. Besides, as Indigo contains 

 an immense proportion of carbon, and, as it is a well-established fact, 

 in Vegetable Physiology, that it is not secreted by plants in the shade, 

 but only when they are exposed to the direct influence of the sun's 

 rays ; it is evident, that Indigo requires much and continued sunshine 

 to render its juices rich in this principle. 



'< The proper period for cutting the plant is previous to flower- 

 ing. The leaves at this time change from a light to a dark green, 

 and, according to the French Indigo planters, they crack when they 

 are squeezed. It is of importance to determine the exact time when 

 the plant comes to this state, since the branches, if they are prema- 

 turely cut, would be deficient in the quantity of the produce, and 

 the quality would be inferior. 



<" The Indigo plant is retained in cultivation for a year, during 

 which period it yields three or four cuttings. The Indigo obtained 

 from the first cutting is the greatest in quantity, and is of the finest 

 quality. The succeeding cuttings become gradually less productive, 

 so that one part of the first yields as much as two parts of the second 

 cutting. 



<* There are several methods employed in the manufacturing of 

 Indigo. The 1st is styled thejermenting process, and is that which 

 was formerly practised in this country, when Indigo was generally 

 cultivated. The branches having been cut by means of a sickle, are 

 placed, with the stalk upwards, in the steeping vat, till it is nearly 

 three parts full. This vat is a large cistern of mason work or wood, 

 about 16 feet square. It is then filled with water, and to prevent 

 the branches from floating, they are kept down by means of rails 

 loaded with planks. Soon after, the fermentation commences, and 

 goes on till, in 24 hours, the contents of the vat are so hot, that the 

 hand cannot be retained in it. The water gradually becomes opaque, 

 and assumes a green colour ; bubbles of carbonic acid gas are emit- 

 ted, and a smell, resembling that of volatile alkali, is exhaled. 

 When the fermentation has gone on sufficiently far, the liquor must 

 be immediately let into the second cistern : for" were it to be allowed 

 to remain after a certain time in the fermenting vat, the pigment 

 would be spoiled ; and if, on the other hand, it were drawn off too 

 soon, much of the Indigo would be lost. This second vat, which is 

 lower than the first, is called the battery, and is commonly in size 

 about 12 feet square, and 4-1 feet deep. Here the liquor is agitated 

 and beaten up, to perform which a variety of machines have been in- 

 vented. The best adapted for the purpose is one with paddles, re- 



