FLAME-HEAT IN THE CHEMICAL LABORATORY. 



389 



to complete the combustion ; yet even with this the flame is 

 hollow in its lower portion, having a cool center, its most in- 

 tense heat being at about three or four inches above the end 

 of the tube in the smaller Bunsen burners, and eight or ten 

 inches in the largest size. If a proper access of air is not 

 allowed to the flame, as sometimes happens in some of the 

 furnace connections occasionally used with Bunsen's burner, 

 acetylene is formed from the imperfect combustion, which is 

 recognized by its disagreeable odor, or by collecting some 

 of the gas formed during the combustion ; the presence of 

 acetylene may be rendered evident by a small amount of a 

 solution of ammoniacal cuprous chloride. 



The best heating effects of the gas used in the ordinary round 

 Bunsen burner, when employed in the heating of crucibles and 

 other vessels, are not obtained; yet in the great majority of 

 cases the small loss of gas is not worth considering, especially 

 as to obtain better results in most cases would only complicate 

 this beautifully simple instrument. 



To get the best effects of heat, we must imitate the principle 

 applied in the Argand burner; namely, to flatten down the exit 

 of the mixed gases. It was 

 by following out this prin- 

 ciple that Mr. Gore was ena- 

 bled to make a burner having 

 a number of radial flat orifices 

 as represented in the figure 

 (1) ; the air from without hav- - 



ing free access to the flame 



along the entire length of the 

 slit openings, the number of 

 slits used are more numerous 

 than those represented in the 

 figure. With the flame from 

 this burner introduced into a 

 certain form of refractory cyl- 

 inders, cast-iron can be melted in a crucible without the aid of a 

 blast, as has already been stated, the little chimney to the fur- 

 nace being two inches in diameter and four feet long. This 

 burner and its furnace is of but limited application, and the 

 amount of gas consumed considerable. 



26 



Fig. 1. 

 The openings at the exit of Gore's burner. 



