UPON GASES AND LIQUIDS. 563 



extended into the upper part of the flame, the great section of 

 which coincided with the equatorial plane. On closing the cir- 

 cuit, the flame was depressed in the centre 3 millims. to 4 millims. 

 below the height of the apices of the poles ; its entire upper 

 boundary had exactly the same form as that in the experiment 

 last described (fig. "J.). The particles of carbon ascending with it 

 united so as to form a black sharply-defined line, which consti- 

 tuted the upper boundary of the flame and ascended as a regular 

 parabola to 180 miUims., and from this spot expanding spirally, 

 again followed the parabolic path to about the same height, and 

 then terminated in the form of an indefinite cloud of smoke out- 

 side the case. 



21. The parabola just described in the case of the turpentine 

 flame, exhibited the same definition when a piece of German 

 tinder was placed under the apices of the poles and ignited. 

 The latter was carbonized without the production of flame, and 

 simultaneously narrow dense columns of smoke ascended. When 

 the circuit was closed at the moment at which one of these passed 

 between the apices of the poles, the parabola was immediately 

 formed. 



The same also occurred, but with a somewhat less distinct 

 outline, with the smoke arising from a tallov) candle which had 

 been blown out. 



22. A small piece of sulphur was placed in a porcelain cup, 

 which was made deep in the centre, and then ignited. After 

 it had become fused into a mass, which was 7 millims. in dia- 

 meter, it burned quietly, and formed a regular cone of flame of 

 about 6 millims. in height, the upper part of which extended to 

 between the apices of the poles. At the moment of closing the 

 circuit the flame was depressed, and then merely formed a layer 

 of fix'e lying upon the fused mass of sulphur. During the mag- 

 netic excitation the sulphur burnt more quickly and boiled 

 violently. 



22 a. When, in the experiment described in the last para- 

 graph, a piece of phosphorus was substituted for the sulphur 

 and ignited, the flame, which burned brightly, was in this case 

 also depressed : this phaenomenon was accompanied with the 

 parabolic ascent of the bluish flame, which has been so frequently 

 described before, and was l.\erc seen in remarkable beauty. 



23. A flame of alcohol, 25 millims. in height and burning 

 steadily with a violet-coloured flame, on closing the circuit, was 



