rre
and rare combination of events, so we need have no hesitation in
postulating such events in our explanation. In the absence of data we
must abandon the analytic or scientific method of investigation, and
must approach it in the synthetic fashion. In a word, instead of taking
known events and deducing from them what has occurred, we must build up
a fanciful explanation if it will only be consistent with known events.
We can then test this explanation by any fresh facts which may arise.
If they all fit into their places, the probability is that we are upon
the right track, and with each fresh fact this probability increases in
a geometrical progression until the evidence becomes final and
convincing.

"Now, there is one most remarkable and suggestive fact which has not
met with the attention which it deserves. There is a local train
running through Harrow and King's Langley, which is timed in such a way
that the express must have overtaken it at or about the period when it
eased down its speed to eight miles an hour on account of the repairs
of the line. The two trains would at that time be travelling in the
same direction at a similar rate of speed and upon parallel lines. It
is within every one's experience how, under such circumstances, the
occupant of each carriage can see very plainly the passengers in the
other carriages opposite to him. The lamps of the express had been lit
at Willesden, so that each compartment was brightly illuminated, and
most visible to an observer from outside.

"Now, the sequence of events as I reconstruct them would be after this
fashion. This young man with the abnormal number of watches was alone
in the carriage of the slow train. His ticket, with his papers and
gloves and other things, was, we will suppose, on the seat beside him.
He was probably an American, and also probably a man of weak intellect.
The excessive wearing of jewellery is an early symptom in some forms of
mania.

"As he sat watching the carriages of the express which were (on account
of the state of the line) going at the same pace as himself, he
suddenly saw some people in it whom he knew. We will suppose for the
sake of our theory that these people were a woman whom he loved and a
man whom he hated--and who in return hated him. The young man was
excitable and impulsive. He opened the door of his carriage, stepped
from the footboard of the local train to the footboard of the express,
opened the other doo