ON HELLEBORUS NIGER. 
227 
5. "White crystalline ; this resembles the refined nitrate. All 
these contain common salt, sulphate and carbonate of soda, mu- 
riate of lime, and occasionally some borate of lime is found under 
the nitrate beds ; one variety of the latter, composed of boracic 
acid, 49.5 ; soda, 8.8 ; water, 26.0 ; lime, 15.7=100, may prob- 
ably become of use in this country in glass making, &e. 
The rough nitrate of soda is broken into several small pieces, 
put into boilers, water introduced, and the whole boiled; the ni- 
trate is held in solution, whilst earthy matter, salt, sulphates, &c, 
are separated and fall to the bottom of the vessel ; the saturated 
solution of nitrate is led into a reservoir, where it deposits any re- 
maining earthy matter ; the clear liquor is run into shallow 
troughs, exposed to the sun ; the nitrate of soda crystallizes, con- 
taining only two to three per cent, of impurities, and is ready to 
be conveyed to the coast for exportation. 
The Pampa de Tamarugal, contains sufficient nitrate for the 
consumption of Europe for ages ; the desert of Atacama, yields 
it ; it has also been met with in the Andes, and in the eastern 
plains. 
ON HELLEBORUS NIGER. 
By G. Walpers. 
M. Walpers gives a minute description of the rhizome of Hel- 
leborus niger, for the purpose of distinguishing it from similar 
roots with which it is liable to be confounded. The plants, 
whose roots seem to be most easily mistaken for the officinal, are 
Helleborus viridis, Adonis vernalis, Actsea spicata, Astrantia ma- 
jor, and Helleborus foetidus. They may be distinguished by the 
following characteristics. 
Helleborus niger. — The dried rhizome is odorless, dark chest- 
nut brown, from the thickness of a swan-quill to that of the little 
finger, drawn up, branching, many-headed, rendered somewhat 
knotty by the cicatrices of the leaf-stalks, the elevated margins of 
which form dish-like excavations, beset with radicles from one to 
two lines in diameter, six to twelve inches in length, and, in 
general, but little branched ; these break with a horny fracture, 
