One end was open, or at least looked as though the end had been shoved several inches into the interior of the box.  I looked into one of the boxes and saw a slit in the wall that had been shoved in.  Kennedy was busy adjusting the apparatus, and paused only to remark that the boxes contained two sensitive selenium surfaces balanced against two carbon resistances.  There was also in the box a clockwork mechanism which Craig wound up and set ticking ever so softly.  Then he moved a rod that seemed to cover the slit, until the apparatus was adjusted to his satisfaction, a delicate operation, judging by the care he took.  Several of these boxes were installed, and by that time it was quite late.

Wires from the apparatus in the art-gallery also led outside, and these as well as the wires from the coils down in the basement he led across the bit of garden back of the Spencer house and up to a room on the top floor.  In the upper room he attached the wires from the storeroom to what looked like a piece of crystal and a telephone receiver.  Those from the art-gallery terminated in something very much like the apparatus which a wireless operator wears over his head.

Among other things which Craig had brought down from the laboratory was a package which he had not yet unwrapped.  He placed it near the window, still wrapped.  It was quite large, and must have weighed fifteen or twenty pounds.  That done, he produced a tape-measure and began, as if he were a surveyor, to measure various distances and apparently to calculate the angles and distances from the window-sill of the Spencer house to the skylight, which was the exact centre of the museum.  The straight distance, if I recall correctly, was in the neighborhood of four hundred feet.

These preparations completed, there was nothing left to do but to wait for something to happen.  Spencer had declined to get alarmed about our fears for his own safety, and only with difficulty had we been able to dissuade him from moving heaven and earth to find Miss White, a proceeding which must certainly have disarranged Kennedy’s carefully laid plans.  So interested was he that he postponed one of the most important business conferences of the year, growing out of the anti-trust suits, in order to be present with Dr. Lith and ourselves in the little upper back room.

It was quite late when Kennedy completed his hasty arrangements, yet as the night advanced we grew more and more impatient for something to happen.  Craig was apparently even more anxious than he had been the night before, when we watched in the art-gallery itself.  Spencer was nervously smoking, lighting one cigar furiously from another until the air was almost blue.