134 
BRITISH PHARMACEUTICAL CONFERENCE. 
When the light from the sun, planets, or fixed stars is observed, these lines 
appear black , but when from the electric spark or an incandescent body, the 
lines are bright , but nevertheless occupy the same position as the dark ones. 
These phenomena are now explained by the grand discovery of spectral 
analysis by Kirchhoff and Bunsen in 1860. They found that when certain 
metals were burnt in a colourless flame they produced bright lines, which 
perfectly coincided with certain of the dark ones noticed in the solar rays. 
For instance, sodium gives a bright yellow line which exactly fits Fraunhofei s 
liu6 D 
Potassium produces two lines, one coincident with the solar line A, and the 
otfcer at the commencement of the violet, and so on with the rest of the metals. 
The extreme delicacy of spectral testing is almost incredible, it is nearly 
impossible often to get a flame free from the sodium line, so minutely universal 
I 
D 
£ Tinct. Ferri 
Perchlor. 
Tinct. Hyos. 
(Bienn.) 
Tinct. Hyos. 
(Annual.) 
Tinct. Cann. 
Ind. 
Tinct. Digitalis. 
Tinct. Cocci 
Tinct. Lacmi. 
is its distribution. Lithium only a few years since was supposed to be com¬ 
paratively rare, because the quantity sometimes present was too small to be 
recognizable by the ordinary tests. Now we find it in almost everything. The 
spectroscope detects it in the ocean and mineral springs, in felspar and granite, 
in' the ashes of plants and milk of animals, in the ash of a cigar and the juice of 
a grape. 
