put the
pieces together and to ask myself what he meant by it all."

"With so much time upon your hands, Dr. Whiles," the Prince remarked,
"you can scarcely fail to have arrived at some reasonable explanation."

"I don't know whether it is reasonable or not," the doctor answered,
"but the obvious explanation is getting on my nerves. There are two
things which I cannot get away from. One is that I cannot for the life
of me imagine your riding a bicycle twelve or fifteen miles north of
London between eleven o'clock and midnight; and the other--"

"Come, the other?" the Prince remarked encouragingly.

"The other," the doctor continued, "is the fact that within half a mile
of my house runs the main London and North Western line."

"The London and North Western Railway line," the Prince repeated, "and
what has that to do with it?"

"This much," the doctor answered, "that on that very night, about half
an hour before your--shall we call it bicycle accident?--the special
train from Liverpool to London passed along that line. You will remember
the tragic occurrence which took place before she reached London, the
murder of the man Hamilton Fynes. If you read the report of the evidence
at the inquest, you will notice the engine driver's declaration that
the only time on the whole journey when he travelled at less than forty
miles an hour was when passing over the viaduct and before entering the
tunnel which is plainly visible from my house."

"This is very interesting," the Prince remarked, "but it is not new. We
have known all this before. Perhaps, though, some fresh thing has come
into your mind connected with these happenings. If so, please do not
hesitate. Let me hear it."

"It is a fresh thing to me," the doctor said,--"fresh, in a sense,
though all the time I have had an uneasy feeling at the back of my head.
I know now what it was which brought Inspector Jacks to see me. I know
now what it was he had at the back of his head concerning the man who
met with a bicycle accident at this psychological moment."

"Inspector Jacks is a very shrewd fellow," the Prince said. "I should
not be in the least surprised if you were entirely right."

The doctor moved restlessly in his chair. His eyes remained on his
companion's face, as though fascinated.

"Can't you understand," he said, "that Inspector Jacks is on your track?
Rightly or wrongly, he believes that you had something to do with the
murder on the train that night."