218 
remain flat, and touch in the centre, in a slope form, it 
will cause the flame to retire towards the axis of the wick- 
pipe whenever the wick is lowered. The consequence is, 
that the wick-hole is less exposed to be heated by the flame. 
To render the flame very brilliant, it is necessary that 
the lamp glass should be six inches high, and at least eight 
or nine lines in its internal diameter. The lower part where 
it is enlarged should be from fourteen to sixteen lines both 
in diameter and height. The higher the tube, the less will 
the flame be disturbed, and indeed will become so steady, 
if it be high and strait, that the lamp may be exposed with- 
out apprehension to the highest wind. The current of air 
nourishing the flame, is so well established that nothing can 
derange it, and the lamp may even be considerably inclin¬ 
ed without the flame leaving the axis of its tube, or black¬ 
ening the sides of the glass. 
If a small covering of thin sheet iron be placed on the 
top of the glass, the lamp will be so completely sheltered 
from wind and rain, that it may be used as a lantern. 
The height of the lamp may be varied according to its 
use. As a substitute for wax candles, or the anti-chamber 
lamp, it should not exceed seven or eight inches. As a 
table lamp, the height of the supporter may be increased 
to ten or eleven inches, and this will neither alter its pro¬ 
perties or its price.* 
Before concluding this memoir, I will take the liberty of 
adding a few observations on the advantages resulting from 
the making of matches for lamps in the mode that I have 
proposed. My ideas may be explained in a few words. 
To make a lamp burn well, it is necessary that the oil 
feeding it, should flow freely on the surface of the small 
* The lamp varnished green or the colour of bronze, together with 
several gildings, costs twelve francs. With its small gauze screen 
and shade, varnished white within, it costs fifteen francs. If var¬ 
nished completely white and richly gilded, the price is seventeen 
francs. 
i 
