144 Orange yellow Earth from the Sikkim Territory. [No. 2. 



partly in the state of the red peroxide,) has been used in modern 

 medicine. The well known Boles of the old Pharmacopseas seem from 

 the description to be both yellow and red ochres, the last either natural 

 or artificial, and they were probably prepared from the yellow-ochres by 

 calcination. 



I find the Sikkim soil to contain in 100 parts 



Hygrometric water, 5.00 



Water and carbonic acid, 0.75 



Iron as peroxide, 1 9.80 



Residuum of Silex and Alumina, 74.45 



100.00 

 The specimen contained no lime or Magnesia and the Silica and Alu- 

 mina were certainly not the active ingredients ? 



I examined, as a comparison, a very pure and bright yellow-ochre 

 from Chota Nagpore in the museum. I find it to contain in 100 parts 



Hygrometric water, 2.75 



Carbonic acid and water of combination, 6.75 



Iron as peroxide, 45.35 



Residuum of Silex and Alumina, 45.15 



100.00 

 The difference then between the two is, that the Sikkim earth con- 

 tains a very little peroxide, from which the red tinge of its orange 

 colour is derived, and about one half the hydrated carbonate which the 

 yellow-ochre does. Its silica too is partly in small fragments which we 

 can scarcely suppose an advantage. But there is a very remarkable 

 property in the iron of the yellow-ochre, and of our Sikkim soil, which 

 the usual officinal carbonate of the shops does not possess, and this may 

 be the key to its efficiency as a curative agent. It is this — 



It was long ago pointed out by Mr. Phillips, in his analysis of the 

 Bath waters, that the Iron, which they are found to contain when a large 

 quantity of the water is evaporated, is not demonstrable by any usual 

 test ; not even by the Tincture of Galls ; but that when a portion of 

 lime water was added to the Assay the Tincture of Galls would then, 

 and then only, produce the usual purple tinge. He assumes thence 

 that the iron exists in some peculiar state. I have also found this 

 in one of our Indian, or rather an ultra Gangetic, mineral water 



