of little difficulty, with this system of using gas, to melt a crucible of
cast iron in an ordinary bed-room fire grate if the front bars are covered
with sheet iron, with a hole (say) three inches in diameter, to admit the
combined gas and air blast. The only care needed is to see that you do not
melt down the firebars during the process. I will also show you how, on an
ordinary table, with a small pan of broken coke and the same blowpipe,
used in the way already described, you can get a good welding heat in a
few minutes, starting all cold. In this case the blowpipe is simply fixed
with the nozzle six inches above the coke, and the flame directed
downward. As soon as the coke shows red, the gas pipe is pinched so as to
blow the flame out, and the mixture of gas and air is blown from above
into the coke as before. With this and a little practice, you can get a
weld on a 7/8 inch round bar in 10 minutes.

There is one use of gas which has already proved an immense service to
those who, in the strictest sense, live by their wits. In a small private
workshop, with the assistance of gas furnaces, blowpipes, and other gas
heating appliances, it is a very easy matter to carry out important
experiments privately on a practical scale. A man with an idea can readily
carry out his idea without skilled assistance, and without it ever making
its appearance in the works until it is an accomplished fact. How many of
you have been blocked in important experiments by the tacit resistance of
an old fashioned good workman, who cannot or will not see what you are
driving at, and who persists in saying that what you want is not possible?
The application of gas will often enable you to go over his head, and do
what, if the workman had his own way, would be an impossibility. When a
man is unable or unwilling to see a way out of a difficulty, a master or
foreman has the power to take the law in his own hands; and when a workman
has been met with this kind of a reply once or twice, he usually gives
way, and does not in future attempt to dictate and teach his master his