Chemistry and Physics. 117 
from actual differences of tint. When the iodid paper is intensely 
bleached it may also be illuminated by a candle flame so that the soda- 
flame produces with this foreign light a white tint nearer to red. 
The potash color-test is not as accurate quantitatively as that for soda. 
It is sufficient for all purposes to distinguish a slight, a strong, and a very 
strong potash reaction, using for comparison in succession the flame of 
oligoclase, orthoclase and leucite heated with gypsum in the same flame 
with the test.. The indigo prism is to be used and the dimensions, color 
and duration of the red flames observed. 
azulite gives a stronger soda reaction than nepheline because it con- 
tains sulphuric acid, and it is always necessary to determine beforehand 
whether the test contains sulphuric acid, chlorine or fluorine. This is 
best accomplished by the common blowpipe. 
For further details we must refer to the original memoir, which must 
create an entirely new department in blowpipe analysis—Ann. der Chemie 
und Pharm., cxi, 257. 
ote—It is easy to see that Bunsen’s memoir contains the solution 
of many chemical and physical problems of great interest. Thus it is 
easy to produce at will a flame which shall have any required tempera- 
ture, at least between certain limits. Since according to Bunsen’s caleu- 
added in each case to the combustible gas in order to produce the re- 
quired temperature. It appears probable that at high temperatures the 
ating power of a body for heat is proportional to its radiating power 
from platinum heated in a furnace with the intensity of the light radi- 
esting results could also be obtained. as to the exact temperature at 
Which bodies become luminous and as to the relative quantities of light 
Same subs nee at different temperatures. ith respect to Bunsen 8 
© or series of minerals containing different but known proportions of 
soda I will suggest that perhaps a series of glasses could be made con- 
to 
30 per cent, so that each number would contain 2 per cent more alkali 
the next lowest number. These would then serve as universal stand- 
Pe o} parison and give much precision to blowpipe observations.— 
Liat 2 W,. G. 
