330 Aphlogistic Lamp. 
Fig. 2,shows the lamp complete. The body of it isa low 
vial, or glass inkstand capable of holding about two ounces 
of alcohol. Itis stopped accurately with a cork, which is 
covered, for ornament, with tin foil. The aperture for ad- 
mitting the tube and wick is made with a hot iron. Disa 
small tube through which the alcoholis poured. A drop- 
ping tube is convenient for this purpose ; but a small fun- 
nel is easily made by cutting off an inch of the neck of a 
broken retort, into which is pushed a cork, and through this 
a small quill. Another orifice still for letting off the air, as 
the alcoho! goes in may be made through the cork. After 
the lamp is charged ; these orifices, are of course, to be clos- 
ed to prevent evaporation. 
When the lamp is completed, and charged, the alcohol is 
inflamed by holding the coil in the blaze ofa candle. After 
letting it burn far a minute or two, the flame is blown out, 
when, if every thing is properly adjusted, the wire will con- 
tinue red hot until the alcohol is exhausted. 
The explanation, why the ignition of the wire is perma- 
nent, seems to be sufficiently simple. Alcohol, when in 
the state of vapour, combines with oxigen with great facili- 
ty. The temperature of the wire is first raised by the flame 
of the candle to about 800° Fah. This degree of heat is 
such as to effect the combination of the alcohol with the ox- 
ygen of the atmosphere. When this is once effected, the 
caloric extricated by the combustion of the alcohol is suffi- 
cient to keep the coil at a red heat, which again is the tem- 
perature at which the alcohol is combustible, so that one 
portionof alcohol, by the absorption of oxygen, and the con- 
sequent extrication of caloric, lays the foundation for the 
combustion of another portion ; and as the alcohol rises in 
a constant stream, so the effect is constant. ‘The stream of 
vapour is much increased by the heat of the lower part of 
the coil, where it embraces the wick, and the temperature 
of the vapour is considerably raised before it reaches that . 
part of the coil where its combustion is effected. Some- 
times, the last or upper turn of the wire only, is kept red 
hot. | 
This lamp, though one of the most curious inventions of 
the age, is not merely a curiosity. The facility and certain- 
ty with which, by means of a match, a light may be obtained 
from it, constitutes its utility. The proper matches for this 
