Every tiny piece is gauged on all its sides
and in every hole and at all points with this double gauge system."
"That doesn't leave much for guesswork," said Hamilton. "But there is
something that's been puzzling me."
"What is that?" asked his guide.
"I've always heard a lot about gun-metal," Hamilton answered, "and yet
all the way through, these parts have been nothing but steel. And all
the guns I ever saw had that bluish look, as gun-metal has. For example,
my watch is what they call gun-metal," and he took it from his pocket
and showed the back of it.
"Gun-metal," said the other, "is an alloy of copper and tin and once was
used almost exclusively for cannon and big guns generally. But you're
right about all guns having a bluish tinge. That is all steel, but it is
treated by a process called coloring or bluing. I'll show you--both the
old way and the new."
Going down the stairs and crossing the yard, he took Hamilton into a
small building where there were a couple of open charcoal furnaces, in
which the charcoal was intensely hot, but not hot enough to catch fire.
The pieces of finished steel were buried in this charcoal, and every
few minutes the men in charge would draw them out, wipe them over with a
bunch of oiled waste, and thrust them back into the fire.
Pages:
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94