"Well," he went on. "Leave them with me. A calligraphic expert may
possibly find some clue to the identity of their writer."
Afterwards, he took up the broken envelope that had contained the
treaty, carefully re-examining its edges by the aid of his large
magnifying glass.
"There is another curious fact that we must not overlook," he observed
slowly. "While the seal has been broken this envelope has also passed
through a `cabinet noir.' See, this edge bears unmistakable traces
after wear in the pocket," and he handed it to me, together with his
glass.
The suggestion was startling, and one that I had entirely overlooked.
The "cabinet noir" is a term well understood in diplomacy, but
unfamiliar perhaps to the general public. Official documents of no
great importance are often sent by post, and in most European countries
this has led to the establishment of a "cabinet noir," in which the
envelope is opened and its contents examined. The mode of procedure is
interesting. The letter to be opened is first shaken well in such a way
that the enclosure falls to one side of the envelope, leaving a space of
about a quarter of an inch between it and the outer edge. This edge is
then placed under an extremely sharp knife worked like a guillotine,
care being taken to put it carefully at right angles to the knife, which
is then brought down and cuts off a slip about one hundredth part of an
inch wide. The envelope is now open, and the enclosure is extracted by
a pair of pincers made for the purpose. After examination it is
replaced, and the ticklish job of removing all trace of the opening has
to be done. This is very ingenious. There are different pots of paper
pulp mixed with a little gum, and each tinted a different colour to suit
the various shades of paper that are operated upon. A very fine
camel-hair brush is dipped into the pot containing the proper tint, and
is then run carefully along the edges which have been cut open. They
are then closed and left under a press for an hour or so, and after
being smoothed with a flat steel instrument, it would take a very clever
expert to notice that the envelope has passed through the "cabinet
noir."
I saw, however, in this worn envelope the two edges were coming apart,
and at once admitted the truth of the Earl's assertions. He was
intensely shrewd; scarcely any minute detail escaped him.
"Well," he said reflectively, at last, "there is but one person from
whom we may ascertain the truth."
"Who?"
"Your wife."
"But she has disappeared."
"We must trace her. She must not escape us," he cried fiercely, with
set teeth. "She has wronged you and acted in collusion with a man who
has betrayed his country and met with a tragic end, even if she herself
did not actually sell the copy of the secret convention to our enemies--
which appears to me more than likely."
"What causes you to believe this?" I inquired, surprised at his sudden
assertion.
"I have a reason," he answered quickly, with an air of mystery. The
cold manner of the expert diplomatist had again settled upon him. "If
it is as I expect, I will show her no mercy, for it is upon me, as
Foreign Minister of Her Majesty, that opprobrium has fallen."
"But she is still my wife," I observed, for even at that moment, when I
had discovered her false and base, I had not ceased to regard her with a
passionate affection.
"Wife!" he snarled angrily. "You would have been a thousand times
better dead than married to such as she." Then he added, "Remain here.
I am going to the telephone to apprise Scotland Yard of her flight. She
only left to-night after the mails were gone, therefore if we have the
ports watched we may yet find her."
And he left me, his quick footsteps echoing down the long corridor.
The moment he had gone I went to his table. Some sudden curiosity
prompted me to endeavour to ascertain what he had been gazing upon so
intently while my back had been turned in penning the instructions to
Sir Philip Emden.
Quickly I took his keys, and, unlocking the tiny drawer, opened it.
Inside there reposed a highly-finished cabinet portrait of my wife.
Amazed to find this picture in the possession of my chief, I took it in
my hands and stood agape. Its pose was unfamiliar, but the reason I had
never before seen a copy of it was instantly made plain. It bore the
name of a well-known St Petersburg photographer.
Ella had lied to me when she had denied ever having been in Russia.