Valuation of Indigo. 289 



experiments, which gave results almost identically the same, 

 shewed that 10 grains of pure indigo require very nearly 7 \ 

 grains of bichromate of potash ; and I have accordingly taken 

 this quantity of the salt for solution in the alkalimeter. 



The following table contains the results of trials upon three 

 series of specimens of commercial indigo, and includes like- 

 wise the price of each sample, and the amount of ash left 

 after careful incineration, as well as the moisture expelled at 

 212°. The first series of samples was obtained from an in- 

 digo broker in London ; the second from Messrs C. Tennant 

 and Co., Glasgow ; and the third from Messrs E. and I. Hen- 

 derson, Glasgow. 



SPECIMENS. 



East Indian 



Spanish 



FIRST 



SERIES. 







Price, 



Alkalimeter 



Ash 



Water 



1851. 



measures 

 consumed. 



per cent. 



per cent 



s. d. 









6 4 



68 



4-5 



5.0 



6 



66 



58 



60 



5 9 



64 



81 



8-0 



5 6 



54 



110 



7-0 



4 9 



51i 



7-2 



7-5 



4 8 



54 



3-6 



70 



4 4 



45 



14-0 



8-4 



4 3 



55 



12-3 



60 



3 10 



50 



130 



7-0 



3 6 



44^ 



190 



5-5 



2 10 



28" 



33-4 



4-5 



SECOND SERIES. 



SPECIMENS. 



Price, 

 1851. 



s. d. 



^YiKanmeier 

 measures 

 consumed. 



Ash 

 per cent. 



Water 

 per cent 



Bengal . . 



. 5 

 . 4 9 



64 



47 



5-9 

 246 



40 



50 



Benares . . 



. 4 6 



45 



207 



8-4 



Guatemala 



. 4 3 



50 



160 



65 



Madras . . 



. 3 8 



41 



106 



67 



Oude . . 



. 3 8 



46 



63 



8-5 



Carraccas . 



. 3 6 



52* 



16 2 



04 



Madras . . 



. 2 9 



35 



333 



60 



