134 



CHEMISTRY. 



verted into a gas and burned, is, interesting to examine in 

 detail. First it is melted by the burning wick, and there is 

 all the while a lake of the melted tallow around it. This is 

 hemmed in by the outer part of the tallow, which is pre- 

 served in the shape of a raised edge, partly because it is so 

 far from the wick, and partly because the cool air, which 

 rises continually to feed the candle's flame, keeps this outer 

 part of the tallow comparatively cool. Sometimes this edge 

 is melted on one side because the wick is bent over so as to 

 be quite near it, and then the tallow runs down from the 

 lake which is about the wick. The next step in the process 

 is the raising of the melted tallow in the wick. This is 

 done by capillary attraction, which is explained in Part I., 

 Chapter VI. Then the tallow is vaporized by the heat, and 

 lastly it is burned that is, it unites with the oxygen of the 

 air, forming carbonic anhydride and water, precisely as is 

 done in the burning of illuminating gas. That water is 

 formed you can prove in the same way that it was proved 

 of the burning of hydrogen gas in the experiment present- 

 ed in Fig. 50. That carbonic anhydride is formed can be 



proved by an experi- 

 ment shown in Fig. 

 51. A small funnel 

 is suspended over a 

 candle, and is con- 

 nected by a tube 

 with a bottle con- 

 taining lime-water. 

 Another tube pass- 

 mm es f rorn this Bottle 

 to the mouth of the 

 experimenter. You 

 see that the tubes are so arranged that by the suction of 

 the mouth the gas from the candle can be made to pass 



