to the receiver, though we had a piece of very fine
wire-gauze put at the bottom of the pipe, between the receiver and the
pipe through which we were forcing the current. In one of these
experiments I was watching the flame in the tube, my son was taking the
vibrations of the pendulum of the clock, and Mr. Wood was attending to
give me the column of water as I called for it, to keep the current up to
a certain point. As I saw the flame descending in the tube I called for
more water, and Wood unfortunately turned the cock the wrong way, the
current ceased, the flame went down the tube, and all our implements were
blown to pieces, which at the time we were not very able to replace."

Stephenson followed up those experiments by others of a similar kind,
with the view of ascertaining whether ordinary flame would pass through
tubes of a small diameter and with this object he filed off the barrels
of several small keys. Placing these together, he held them
perpendicularly over a strong flame, and ascertained that it did not pass
upward. This was a further proof to him of the soundness of the course
he was pursuing.

In order to correct the defect of his first lamp he resolved to alter it
so as to admit the air to the flame by several tubes of reduced diameter,
instead of by a single tube. He inferred that a sufficient quantity of
air would thus be introduced into the lamp for the purposes of
combustion, while the smallness of the apertures would still prevent the
explosive gas passing downwards, at the same time that the "burnt air"
(the cause, in his opinion, of the lamp going out) would be more
effectually dislodged. He accordingly took the lamp to a tinman in
Newcastle, and had it 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) the one tube opening directly under the flame.

This second or altered lamp was tried in the Killingworth pit on the 4th
November, and was found to burn better than the first, and to be
perfectly safe. But as it did not yet come quite up 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