12 Sir Humphry Davy on the fire-damp of coal mines, and on 
it is only necessary to use air-tight lanterns, supplied with air 
from tubes or canals of small diameter, or from apertures 
covered with wire gauze placed below the flame, through 
which explosions cannot be communicated, and having a 
chimney at the upper part, on a similar system for carrying 
off the foul air ; and common lanterns may be easily adapted 
to the purpose, by being made air-tight in the door and sides, 
by being furnished with the chimney, and the system of 
safety apertures below and above. 
The principle being known, it is easy to adopt, and multi- 
ply practical applications of it. 
The first safe lantern that I had constructed, was made 
of tin-plate, and the light emitted through four glass plates in 
the sides. The air was admitted round the bottom of the flame 
from a number of metallic tubes of of an inch in diameter, 
and an inch and £ long. The chimney was composed of two 
open cones, having a common base perforated with many 
small apertures, and fastened to the top of the lantern, which 
was made tight in a pneumatic rim containing a little oil; the 
upper and lower apertures in the chimney were about ~ of 
an inch : the lamp, which was fed with oil, gave a steady 
flame of about an inch high and half an inch in diameter. 
When the lantern was slowly moved, the lamp continued to 
burn, but more feebly, and when it was rapidly moved, it 
went out. To obviate this circumstance, I surrounded the 
bottom of the lantern with a perforated rim; and this ar- 
rangement perfectly answered the end proposed. 
I had another chimney fitted to this lantern, furnished with 
a number of safety tin-plate tubes of the sixth of an inch in 
diameter and two inches long : but they diminished consi- 
