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_ 4. Mr. Thiselton-Dyer would recommend, with the approval of the 
| Secretary of State, that ced subject be brought to the notice of Her 
Majesty's Minister at Bue os Ayres, who may be — to assist in 
E the investigation of an iesti subject. 
e, Ke. 
= (Signed) OR Monee 
_ Sir Villiers Lister, K.C.M.G., 
Foreign Office, S,W. 
3^ eo December last a case containing a supply of leaves was received at . 
Kew and forwarded to Professor Hummel, of the Yorkshire College, 
csl It may be E nd that the leaves were ina dry condition, 
Toly co mmunicated to this establishm 
‘he conclusion arrived at xd rnm that the leaves must be 
ud on the spot in a fresh state, There is undoubtedly indigo in 
ein ves, and the phit might be utilised locally for supporting an 
X indigo industry in the new world. The plant is singularly 
ardy, e as su by Mr. Egerton, “ it might some SAT: compete 
i the European market with Indian i indigo.” 
Professor Hummer to Royat Garpens, KEW. 
The Yorksħire College, Leeds, 
14 June 1892. 
* * z 
WirH respect to the Eupatorium tinctorium leaves received 
time se I find they yield an extremely small quantity of indigo, 
ing to the mposition of the * indican" ori originally 
t. Fa sent a sample of the leaves to Dr. Schunck, who is our 
t authority on this subject, and he wrote me as follows :— 
certainly do contain indiean but the quantity is very 
sill I tried several ways of obtaining, not indican, but the npe: 
nting it,from the leaves, but all the methods except o 
i is met s :—The vase ioe 









ca. 
small quantity of sugar of lead solution was added, 
r dirty yellow vécipióite was filtered off and to the yellow filtrate an 
excess of hydrochloric acid or a little nitric acid was added. On standing, 
idigo blue separated ; this was filtered off and treated first with boiling | 
r and then with caustic lye, then dried. In this way the enclosed _ 
i aens were obtained, each d 100 grains of leav ves, No. 1 using 
.and No. 2 usi HNO,. In my opinion the only way of ascer- — — 
the value of of the leaves ir} producin g nig i is by Working: them /—— 
( Mega at Ame place where the plant grows 2 
ini do. 
iene)” 3. 3. Hone 
i 



