now at rest and kept so by means of a lever that prevented all
vibration whatever.

"See, I release this lever--now, let no one in the room move.
Watch the needles on the paper as the clockwork revolves the
drums. I take a step--ever so lightly. The pendulums vibrate, and
the needles trace a broken line on the paper on each drum. I
stop; the lines are practically straight. I take another step and
another, ever so lightly. See the delicate pendulums vibrate?
See, the lines they trace are jagged lines."

He stripped the paper off the drums and laid it flat on the table
before him, with two other similar pieces of paper.

"Just before the time of the rapping I placed this instrument in
the corner of the Vandam cabinet, just as I placed it in this
cabinet after Mr. Jameson conducted you from the room. In neither
case were suspicions aroused. Everything in both cases was
perfectly normal--I mean the 'ghost' was in ignorance of the
presence, if not the very existence, of this instrument.

"This is an improved seismograph," he explained, "one after a
very recent model by Prince Galitzin of the Imperial Academy of
St. Petersburg. The seismograph, as you know, was devised to
register earthquakes at a distance. This one not only measures
the size of a distant earthquake, but the actual direction from
which the earth-tremors come. That is why there are two pendulums
and two drums.

"The magnetic arrangement is to cut short the vibrations set up