344 J. L. Smith on flame heat in the Chemical Laboratory. 
The use of the flattened burner is not fully appreciated ; its 
advantages are, that there is no cold point in the flame, and the 
burner can be brought much nearer to the object to be heated, 
within 20 to 25 millimeters for the small sized burners. 
this burner as usually made, the opening is too broad, experi- 
ence having convinced me that a slit 2 millimeters across and 
2. 3. 
a burner, consuming 54 to 
cubic feet of gas per hour, I 
conduct most effectually all 
silica fusions in one hour or 
less, taking care to protect 
the crucible from the current 
of the air by a properly con- 
structed short conical chim- 
ney, which chimney can be 
; : ‘ made of soap stone, sheet 
iron, or any other convenient material. 
S was stated in the commencement of this article, it was 
more recent modifications, will be published in a very short 
e description of it, with all the minute details of 
‘ manipulation, being ready for the press. 
Ra eee nee NT a ee eT 
