1896-97.] Electrical Properties of Fumes from Charcoal. 317 
one of these holes, and was thrust into the burning fuel. It was 
noticed that when the burning charcoal was first put in position 
below the funnel it always produced negative electrification, which 
ultimately changed to positive. Thus, in four experiments, the 
electrification, which was at first negative, became positive after 8, 
10, 14, and 18 minutes respectively. On investigation it was 
found that as long as any flame * was visible in the burning char- 
coal the electrification was negative ; but as soon as all the flame 
disappeared, leaving only the red glow, the electrification became 
* In a paper on “Electrification of Air by Combustion,” by Magnus 
Maclean and Makita Goto, communicated to the Philosophical Society of 
Glasgow on November 20, 1889, is a statement of results of many observa- 
tions to find the potential to which the insulated quadrant of a quadrant 
electrometer is raised when in metallic connection with various kinds of flames 
and fires. It is there said: “The effect of an ordinary lucifer match 
is very interesting. While the match is burning with a flame the deflection 
indicates positive electrification ; but after the flame ceases the electrification 
becomes negative, the effect now being that of glowing charcoal.” The follow- 
ing table is quoted from that paper. In some cases the burnings lasted so 
short a time that quantitative determinations of the potential were not ob- 
tained. It is conceivable that all of the complementary opposite electricity 
separated from that which went to the electrometer in those experiments went 
to uninsulated solids in the neighbourhood. The experiments described in 
the text demonstrate that some of it was lodged in the air and fumes proceed- 
ing from the fire or flame. 
Substances giving Flames or 
Burnings. 
Electrification of 
Insulated Fuel. 
Greatest observed 
Potential in Volts. 
Charcoal ...... 
Negative 
3*0 
Lucifer match, wood, and paper glowing 
3 5 
3*0 
Hydrogen ...... 
3 9 
0-6 
Iron burning in vapour of sulphur 
9 9 
. . . 
Copper ,, ,, 
9 • 
. . . 
Paraffin lamp ..... 
Positive 
0-6 
Alcohol lamp ..... 
9 5 
0-3 
Sulphur ...... 
2-0 
Phosphorus exposed to air . 
? i 
1-5 
Magnesium ..... 
9 9 
. . 0 
Iron burning in oxygen 
Lucifer match, wood, and paper burn- 
9 9 
... 
ing with flame .... 
9 9 
Bisulphide of carbon .... 
9 9 
6*6 
Sulphuric ether ..... 
9 9 
0*9 
Turpentine ..... 
9 9 
0*5 
Beeswax ...... 
3 3 
0*7 
Camphor ...... 
3 3 
