bottle of Draper's dichroic ink. I obtained, by
a simple ruse, a specimen of the office notepaper and the ink. We will
examine it presently. I found that Mr. Barlow is a new tenant, that he
is rather short, wears a wig and spectacles, and always wears a glove on
his left hand. He left the office at 8.30 this morning, and no one saw
him arrive. He had with him a square case, and a narrow, oblong one
about five feet in length; and he took a cab to Victoria, and apparently
caught the 8.51 train to Chatham."

"Ah!" exclaimed the inspector.

"But," continued Thorndyke, "now examine those three letters, and
compare them with this note that I wrote in Mr. Barlow's office. You see
that the paper is of the same make, with the same water-mark, but that
is of no great significance. What is of crucial importance is this: You
see, in each of these letters, two tiny indentations near the bottom
corner. Somebody has used compasses or drawing-pins over the packet of
notepaper, and the points have made little indentations, which have
marked several of the sheets. Now, notepaper is cut to its size after it
is folded, and if you stick a pin into the top sheet of a section, the
indentations on all the underlying sheets will be at exactly similar
distances from the edges and corners of the sheet. But you see that
these little dents are all at the same distance from the edges and the
corner." He demonstrated the fact with a pair of compasses. "And now
look at this sheet, which I obtained at Mr. Barlow's office. There are
two little indentations--rather faint, but quite visible--near the
bottom corner, and when we measure them with the compasses, we find that
they are exactly the same distance apart as the others, and the same
distance from the edges and the bottom corner. The irresistible
conclusion is that these four sheets came from the same packet."

The inspector started up from his chair, and faced Thorndyke. "Who is
this Mr. Barlow?" he asked.

"That," replied Thorndyke, "is for you to determine; but I can give you
a useful hint. There is only one person who benefits by the death of
Alfred Hartridge, but he benefits to the extent of twenty thousand
pounds. His name is Leonard Wolfe, and I learn from Mr. Marchmont that
he is a man of indifferent character--a gambler and a spendthrift. By
profession he is an engineer, and he is a capable mechanician. In
appearance he is thin, short, fair, and clean-shaven, and he has lost
the middle