THE AORICULTUBAL JOURNAL. m 



There are two factors which have pre- ' 

 vented the adoption of the analytical 

 basis of valuation more than anything 

 else. One is a want of some standard 

 and recognised method for the determina- 

 tion of percentage of indigotin ; the other 

 is vested interest. The first objection 

 should be easily overcome, as while 

 widely differing results are apt to be 

 obtained when different methods are 

 used, when two expert operators use the 

 same process identical results are obtained. 

 It does not matter very much whether 

 the figure obtained represents the actual 

 percentage of indigotin ; it i3 only neces- 

 sary that when the same sample be ex- 

 amined by several analysts, their figures 

 shall agree very closely. 



The writer has found that the method 

 in which indigo is dissolved in concen- 

 trated sulphuric acid, the solution diluted 

 to a known volume, aliquot part removed 

 with a pipette, the indigotin precipitated 

 by saturation with common salt, and the 

 resulting precipitate dissolved in dilute 

 sulphuric acid, titrated with permanga- 

 nate of potassium, has gi /en the most 

 constant results. This method is rapid, 

 and any intelligent educated native of 

 India can be taught in a few weeks to 

 use it so as to obtain results in which for 

 the same sample the percentage of indigo- 

 tin will not vary more than 0*3 per cent. 

 It is absolutely necessary that this or 

 some other method should be used as a 

 basis for the buying and selling of indigo, 

 that some agreement shall be come to 

 among the analysts, and that the fullest 

 and minutest directions as regards strength 

 of acid solution, the amount of dilution, 

 size of dishes, and time shall be published. 

 As regards the second objection — i.e., the 

 use of an analytical basis — it is to be 

 remembered that while some indigos 

 would obtain their price, other indigos 

 bearing old and well-known favourite 

 marks would not sell at such good rates 

 as in the past ; and those interested in 

 the long established indigo auction busi- 

 ness in Calcutta might suffer in pocket. 

 There is also another argument in favour 

 of buying and selling it on a more scien- 

 tific basis than that at present in vogue. 

 It is this : Many attempts have been made 

 to improve the manufacture of indigo as 

 regards quality and quantity produced, 

 but hitherto the great difficulty has been 



that any alteration in the method of 

 working was likely to yield an indigo 

 differing more or less in physical appear- 

 ance from that usually sold at the Calcutta 

 auctions. In consequence such indigo, 

 however rich it might be in indigotin, 

 and however suitable for the purpose of 

 the dye, was apt not to find a good mart. 

 There have been fashions in indigo as in 

 everything else, and it is almost impos- 

 sible for any improvement to be made in 

 the factory so long as the price of the 

 product is to be made dependent upon 

 some minute difference in shade or other 

 physical appearance. It is not likely that 

 if an analytical basis comes into general 

 use the European indigo planters, most of 

 whom are interested in Behar factories, 

 are likely to profit directly from the 

 change. But the real advantage which 

 the planter would reap is this, that with a 

 sound and unvarying basis for the buying 

 and selling of his produce, based upon 

 chemical principles, he will be able to 

 employ the aid of chemistry to help him 

 to obtain larger yields and a purer article, 

 without the fear that his indigo will be 

 unsaleable on account of its looking a 

 little different from what has appeared 

 before in the Calcutta market. 



Of late years the economical production 

 of artifical indigo has appeared to threaten 

 the planting industry ; that such a danger 

 is real no thinking person can but admit 

 when one considers the disastrous effects 

 which the introduction of alizarin had 

 upon the madder planting industry. How 

 long will it be before the artificial indigo 

 is put on the market at such prices and in 

 such quantities as to render indigo plant- 

 ing an unprofitable undertaking no one 

 can prophesy, but it appears that if the 

 planter working on the present un- 

 scientific system is able to produce indigo 

 at a lower price than the artificial product 

 with a good margin of profit, as is done 

 at present, that if the industry was to be 

 run on thoroughly scientific lines, such a 

 further reduction in cost of production 

 would result as to render it impossible 

 for the artificial indigo to compete with 

 the natural for many years to come. Of 

 course no one but those chemists investi- 

 gating artificial indigo can know what the 

 actual cost of production is, and there is 

 no certainty at what time artificial indigo 

 will be on the market at a price lower 



