The life of George Stephenson, railway engineer - Lighthouse ...

CHAP. X.] TESTS HIS SECOND AND THIRD LAMPS. m
altered so that the air was admitted by three small tubes inserted
in the bottom of the lamp, the openings of which were placed on
the outside of the burner, instead of having (as in the original
lamp) one tube opening directly under the flame.
This second or altered lamp was tried in the Killingworth pit
on the fourth of November, and was found to burn better than
the first lamp, and to be perfectly safe. But as it did not yet
come up entirely to the inventor's expectations, he proceeded to
contrive a third lamp, in which he proposed to surround the oil
vessel with a number of capillary tubes. Then it struck him,
that if he cut off the middle of the tubes, or made holes in metal
plates, placed at a distance from each other equal to the length
of the tubes, the air would get in better, and the effect in pre-
venting the communication of explosion would be the same. " I
thought," he says, " that the air would have easier access, and
the effect might be the same if I cut away the middle of the
tubes ; and that the flame, if it passed through the apertures at
top, would not communicate the explosion to the hydrogen be-
yond the plate below. I constructed a lamp upon this principle,
and found that, the holes having been punched very small, the
flame never passed even through the first plate." *
Stephenson was encouraged to persevere in the completion of
his safety lamp, by the occurrence of several fatal accidents
about this time in the Killingworth pit. On the 9th of Novem-
ber, a boy was killed by a blast in the A pit, at the very place
where Stephenson had made the experiments with his first
lamp ;
and, when told of the accident, he observed that if the boy
had been provided with his lamp, his life would have been
saved.
The third safety lamp, as finally designed by Stephenson, was
in the hands of the manufacturer on the 24th of November,
before he had heard of Sir Humphry Davy's experiments, or of
the lamp which that gentleman proposed to construct. And this
third lamp was finished, and tried in the Killingworth pit, on the
30th of the same month. On the 5th of December, Stephenson
* A Description of the Safety Lamp, invented by George Stephenson, and
now in use in the liillingworth Colliery. London: Baldwin, CradoCk, and Joy,
ISir, p. 8.