"Very fine chains are much alike," I managed to say. "For all I
know, this may be mine, but I don't know how it got into that
sealskin bag. I never saw the bag until this morning after daylight."

"He admits that he had the bag," somebody said behind me. "How did
you guess that he wore glasses, anyhow?" to the amateur sleuth.

That gentleman cleared his throat. "There were two reasons," he
said, "for suspecting it. When you see a man with the lines of his
face drooping, a healthy individual with a pensive eye,--suspect
astigmatism. Besides, this gentleman has a pronounced line across
the bridge of his nose and a mark on his ear from the chain."

After this remarkable exhibition of the theoretical as combined with
the practical, he sank into a seat near-by, and still holding the
chain, sat with closed eyes and pursed lips. It was evident to all
the car that the solution of the mystery was a question of moments.
Once he bent forward eagerly and putting the chain on the window-sill,
proceeded to go over it with a pocket magnifying glass, only to shake
his head in disappointment. All the people around shook their heads
too, although they had not the slightest idea what it was about.

The pounding in my ears began again. The group around me seemed to
be suddenly motionless in the very act of moving, as if a hypnotist
had called "Rigid!" The girl in blue was looking at me, and above
the din I thought she said she must speak to me--something vital.
The pounding grew louder and merged into a scream. With a grinding
and splintering the car rose under my feet. Then it fell away into
darkness.