1836.] Miscellaneous. 317 



round by Mr. Gordon, the Secretary to the Tea Committee, and obliging- 

 ly given to me by Mr. Grant, of the Honourable Company's Export Ware- 

 house. How very alike they seem, you will at once have noticed, and 

 their analysis gives as follows : — < 



Tea soils of Assam. Tea soil of China. 

 Surface At 2§ feet 

 soil. deep. 



Water . 2.45 2.00 3.00 



Vegetable matter ~ 1.00 .80 1.00 



Carbonate of Iron 7.40 6.70 9.90 



Alumina 3.50 5.45 9.10 



Silex ~ 85.40 84.10 76.00 



99.75 99.05 99.00 



Traces of phosphate and sulphate") „,. 



of lime and loss, 1_J ' 25 * 95 L0 ° 



100.0 100.00 10.000 

 There are two peculiarities in these soils ; the first, that they contain no 

 carbonate of lime, and only traces of phosphate and sulphate ; and the 



next, that their iron is almost wholly in the state of carbonate of iron a 



widely different compound from the simple oxides. They would be called 

 poor yellow loams ; and cotton, tobacco, or sugar-cane would probably 

 starve upon them : but we find that they suit the tea plant perfectly. 

 It is a striking coincidence, that we should find our tea soils and those of 

 China so exactly alike. 



I fear to grow prolix, though I have much more to say on the subject 

 of soils ; I shall therefore break off, trusting that for the present I have 

 amply shown the necessity of a careful examination of the soil ; and that 

 the commercial public, who can do so much for us in this way, will not 

 neglect their own interests in procuring specimens of soils for us ; for to 

 go to work in ignorance of this great element of success, is absolutely to 

 blunder on in the dark where chemistry would lend us an unfailing light. 



[We have also received specimens of the tea soils for analysis, but for want of 

 space must postpone the notice of ourresults, which agree for the most part with Mr. 

 Pidoington's. We have also au analysis of the Assam tea soil by Dr. McClel- 

 land. — Ed.] 



3. — Action of Copper on Ink. 



A curious case lately came under my notice of the effect of saline mois. 

 ture and copper united on writing ink. The Bengal Bank referred to my 

 examination three bank notes sent in by a native, who protested he knew 

 not how the numbers and signatures had disappeared ; that he had left 

 them in a small copper box on his departure into the country, having 

 precisely noted the amounts and numbers — and that on his return they 

 were thus altered. The Secretary of the Bank disbelieved the marvellous 

 statement, because the endorsements remained untouched. 



I conceived it would be very easy, at first sight, to restore the writing 

 by the usual method of slightly acidifying the paper, and then testing 

 with prussiate of potash, which if the smallest traces of the iron remained, 

 would develops the letters in blue. The only effect however of the appli- 

 cation of this re-agent was to develope a copious red-brown upon the 

 entire surface of the paper, proving how strongly it had been impregnated 

 with a solution of copper : — in one of the three papers there was a general 

 faint blue where the signature might be expected, but not the faintest 

 trace of a number or letter could be recovered. It immediately occurred 

 to me, that a solution of copper would in fact dissolve away the iron while 

 it deposited the copper, and thus leave none of the former metal to be 

 acted upon by the prussiate. To prove this point beyond a doubt, I select- 



