116 Scientific Intelligence. 
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sium may be detected with perfect distinctness. 
The detection of lithia in the presence of potash and soda is 
effected by looking at the flame through a hollow prism filled with 
lution of sulphate of indigo. The carmine-red color of the lithia 
disappears when a certain thickness of solution is reached, and if 
be put upon the prism, all the layers of liquid above the mark w 
only the red potash-rays to pass through. Lime and soda have 
ence on this reaction. When potash and lithia are both pre 
flame from the salt to be tested should be compared with that of pl 
potash. The flame containing lithia and potash appears through 
layers of liquid redder than the potash flame alone; through thick 
layers the potash flame appears scarcely weakened. In this manner s0l 
thousandths of lithia may the discovered in potas “ 
To render these processes available for silicates Bunsen mixes the mi 
eral with pure um and heats in the melting space, when siliealé 
arranges a scale of minerals for comparison according to the cont 
soda in each. These are— 
NaO __ Ko 
1. Lazulite, - “ 9-09 ; 
2. Nepheline, - a AAD pg - 494 
3. Albite, - i 10°06 : ~ 
4, Orthoclase, . $a OG tm 7-08 
5. Sanidin, - F 4:0 in 80 
6. Labradorite, - eee ee - 106 
7. Anorthite, — - “ jaieg ‘ 0°62 — 
8. Leucite aa Be la +, 2 Sa 
