So it happened that these mines were killing several times as many men
as other mines throughout the country.

Was there no remedy for this, Hal asked, talking with one of his
mule-drivers, Tim Rafferty, the evening after his ride with Cho. There
was a remedy, said Tim--the law required sprinkling the mines with
"adobe-dust"; and once in Tim's life, he remembered this law's being
obeyed. There had come some "big fellows" inspecting things, and
previous to their visit there had been an elaborate campaign of
sprinkling. But that had been several years ago, and now the apparatus
was stored away, nobody knew where, and one heard nothing about
sprinkling.

It was the same with precautions against gas. The North Valley mines
were especially "gassy," it appeared. In these old rambling passages one
smelt a stink as of all the rotten eggs in all the barn-yards of the
world; and this sulphuretted hydrogen was the least dangerous of the
gases against which a miner had to contend. There was the dreaded
"choke-damp," which was odourless, and heavier than air. Striking into
soft, greasy coal, one would open a pocket of this gas, a deposit laid
up for countless ages, awaiting its predestined victim. A man might sink
to sleep as he lay at work, and if his "buddy," or helper, happened to
be out of sight, and to delay a minute too long, it would be all over
with the man. And there was the still more dreaded "fire-damp," which
might wreck a whole mine, and kill scores and even hundreds of men.

Against these dangers there was a "fire-boss," whose duty was to go
through the mine, testing for gas, and making sure that the
ventilating-course was in order, and the fans working properly. The
"fire-boss" was supposed to make his rounds in the early morning, and