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Chemistry and Physics. 115 
C., 2586 C., or as a mean, 2350 C., so that the temperature of the flame 
where the quantity of air is exactly sufficient for the combustion of the 
gas, may be assumed in round numbers as 2300 C. It is easy to see, 
however, that the temperature will vary in different parts of the flame. 
The author gives a simple and elegant method of determining the point 
of maximum temperature by introducing a platinum wire into the flame, 
and determining at what point the light emitted by this is most intense. 
In this manner it is found that the zone of maximum temperature lies in 
the external cone of flame, a few millimetres above and below the apex 
of the internal non-luminous cone, which is on a level with the upper 
base of the chimney. The author employs this zone to investigate the 
action of a temperature of 2300 C. upon different substances, and terms 
it the melting space. The outer border of this melting space acts as an 
oxydizing flame, the inner as a reducing flame, the reduction being most 
complete evaporation determined by means of a seconds pendulum or a 
onom , 
ol chlorid of potassium is 15°33; of chlorid of sodium 6°57; of phos- 
Phoric acid 23-00. Other substances are more or less completely decom- 
posed at the temperature of 2300 C. 
ides its use in experiments on volatility the flame may also be em- 
ced. Th 
mond lustre so long as the rays of the soda flame fall upon it, and this 
pee ordinary lamplight or daylight. A still more delicate reaction 
af 
by a movable arm. If we introduce the smallest quantity of a soda 
compound into the melting space, the red paper appears white, with a 
8. hg introduced into the li uid will take up a drop which 
eee gently evaporated to dryness and then tested as before. In this 
. Toys a milligram of common salt may be easily detected 
iolet wae Potash compounds, as is well known, communicate a bluish 
ce et tint which is completely concealed by small quantities of soda, 
this case the potash may easily be detected by means of Cartmell’s 
