ting to get their safety-lamps before going down for the day shift.

As in most well-organized collieries, the safety-lamps were filled and
adjusted by experts, who looked after nothing else. After the lamps
were lighted, they were locked--and not one of the miners was allowed
a key. Thus the lamps could not be opened below ground and there was
no chance for a reckless man to expose a naked flame in a room or
entry where there might chance to be gas. A safety-lamp would not go
out unless the air in the mine was so vitiated that it was dangerous
to life to remain therein, or unless there was some defect in the lamp
which would render it perilous to use.

After the lamps had been given out, Clem and Anton got in the cage to
go down the shaft. Otto happened to be descending at the same time.

"We're still waiting for your 'knockers' to show themselves!" Clem
suggested jestingly.

The old man deigned no reply. Instead, he looked round the cage
meaningly at the other men there, most of whom frowned at Clem's
remark. Among miners, it is believed to bring bad luck to speak or
even to hint of accidents when in the cage. Only Otto's personal
liking for the young fellow kept him from a retort which might have
brought on a quarrel.

On reaching the bottom, Clem and Anton set out along the man-way
together. It was a walk of nearly a mile underground from the main
shaft of the mine to the distant "room" or square hole in the seam,
where Clem was to dig away the coal face, and which was one of the
rooms from which Anton was loading coal.

This Ohio colliery was being worked on what is known as the
pillar-and-room method. This consists in dividing the seam of coal
into squares like a chessboard, taking out the coal from each
alternate square, leaving the intervening squares of coal intact to
act as pillars in holding up the roof. They do not look like pillars
to a careless observer, often being blocks of coal thirty yards
square.

"It seems silly," said Anton, after they had walked on a minute or
two, "to leave all this coal near the shaft and to go digging a mile
away. Why not take all the coal that is handy first?"

"And have the roof come down and block up all the coal that is beyond?
That would be just throwing away the wealth of the mine."

"Timber the roof, then!"

"It would cost too much, for one thing," Clem explained, "and, for
another, all the timber in the world won't hold up a roof if the
excavation is made to