reddish powder.

Kennedy took a little powder of another kind from the other
bottle and lighted it with a match.

"Stand back--close to the wall," he called as he dropped the
burning mass on the red powder. In two or three leaps he joined
us at the far end of the room.

Almost instantly a dazzling, intense flame broke out, and sizzled
and crackled. With bated breath we watched. It was almost
incredible, but that glowing mass of powder seemed literally to
be sinking, sinking right down into the cold steel. In tense
silence we waited. On the ceiling we could still see the
reflection of the molten mass in the cup which it had burned for
itself in the top of the safe.

At last it fell through into the safe--fell as the burning roof
of a frame building would fall into the building. No one spoke a
word, but as we cautiously peered over the top of the safe we
instinctively turned to Kennedy for an explanation. The Central
Office man, with eyes as big as half-dollars, acted almost as if
he would have liked to clap the irons on Kennedy. For there in
the top of the safe was another hole, smaller but identical in
nature with the first one.

"Thermit," was all Kennedy said.

"Thermit?" echoed Andrews, shifting the cigar which he had
allowed to go out in the excitement.