230 



METALLOIDS. 



platinum also may be readily fused. The apparatus 

 represented in the figure, furnishes a simpler means of 

 obtaining similar results/ An abundant flow of hy- 

 drogen is required, and a pint bottle should, therefore, 

 be employed in its preparation. To retain it free from 

 water, which would tend to reduce the heat of the 

 flame, a little cotton may be introduced into the bowl 

 of the pipe through which it passes. In evolving the 

 oxygen, only a part of the tube should be heated at a 

 time, lest the gas should be too rapidly evolved. 



FLAME CONTINUED. The student will 

 ture of flame already have found abundant evidence that 

 {rairf UlU8 ~ air or ox yg en * s essential to combustion. 

 A still more striking illustration of the sub- 

 ject remains to be given. A phosphorus 

 match, if suddenly introduced into the 

 interior of a flame, notwithstanding the 

 high temperature in its vicinity, is not 

 ignited. The wood burns off, but the 

 phosphorus of the match does not un- 

 dergo combustion. The same principle 

 may be illustrated by holding a match 

 for a moment through the body of the 

 flame. It is consumed at the sides, 

 while the centre remains unburned. 



