544 M. W. HankePs Account of some Eocperiments 



ciently great. It will be afterwards shown by experiment that 

 the result last nientiomed actually occui-s. 



But it is not the size of the flame alone which detennines the 

 character of the current, it also depends upon the intensity of 

 the combustion. The portions of the lamp No. 2 which surround 

 the wick are exactly of the same dimensions as the corresponding 

 parts of No. 1 . In the experiment, however, the wick of No. 2 

 was a simple one, and had been used for some time. On raising 

 it until a flame of equal magnitude with the former was attained, 

 the needle still showed a weaker current. Even the lamp No. 1 

 itself, after having burnt for some time, was no longer able to 

 cause a divergence of 20°. 



The inclined position, which, as before stated, was given to 

 the platinum foil, is more favourable than the horizontal, for 

 the latter causes a weaker combustion. When the platinum was 

 held at some height above the chimney, and was changed from 

 a horizontal to an inclined position, the angle was increased by 

 the change from 9° to 10°; this is a natural result of the fact, 

 that a greater draft is pei*mitted by the latter position, and thus 

 the power of the flame is increased. The platinum being held 

 high above the chimney in a horizontal position, an angle of 5° 

 was observed; and on inclining it, the angle increased to 6°-8. 



As might be expected, the artificial introduction of a current 

 of air also increases the action. This was effected by means of 

 the bellows attached to lamp No. 2. The platinum foil was first 

 held over the chimney, and before the bellows were applied, an 

 angle of 1° was obtained; when the bellows were set in action- 

 the needle mounted to 10^*6, and on continuing to blow, rose to 

 116°(11°-6?T.)'^ 



The different specimens of alcohol and sether which I applied 

 gave currents of different power. In order to obtain results 

 which might be compared with each other, I poured the fluid 

 into a small platinum crucible and ignited it. With the crucible 

 one end of the wire of the galvanometer was connected, and to 

 the other end a piece of platinum foil was attached which was 

 dipped into the flame in an inclined position, so that the distance 

 of itg upper edge from the rim of the crucible was i2'l millims., 

 while its lower edge was 21*5 millims. distant. The crucible as 

 well as the platinum remained unmoved during the entire series 

 of experiments. The fluid in this case burnt without a wick. 

 On pouring alcohol of the specific gravity 0-850 into the vessel 

 and igniting it, an angle of 0° 8 was observed ; this was increased 

 to 1°-1 when alcohol of the specific gravity 0'835 was used, and 

 amounted to 2°*6 with absolute alcohol. The latter angle, how« 

 ever, remained constant only so long as the alcohol remained 

 without boiling; when it boiled, an angle of 5°-5 was obtained; 



