im as
I trust myself."

"At what hour was the office closed on Monday?"

"At five."

"Did you close it?"

"I am always the last man out."

"Where were the plans?"

"In that safe. I put them there myself."

"Is there no watchman to the building?"

"There is, but he has other departments to look after as well. He is an
old soldier and a most trustworthy man. He saw nothing that evening.
Of course the fog was very thick."

"Suppose that Cadogan West wished to make his way into the building
after hours; he would need three keys, would he not, before he could
reach the papers?"

"Yes, he would. The key of the outer door, the key of the office, and
the key of the safe."

"Only Sir James Walter and you had those keys?"

"I had no keys of the doors--only of the safe."

"Was Sir James a man who was orderly in his habits?"

"Yes, I think he was. I know that so far as those three keys are
concerned he kept them on the same ring. I have often seen them there."

"And that ring went with him to London?"

"He said so."

"And your key never left your possession?"

"Never."

"Then West, if he is the culprit, must have had a duplicate. And yet
none was found upon his body. One other point: if a clerk in this
office desired to sell the plans, would it not be simply to copy the
plans for himself than to take the originals, as was actually done?"

"It would take considerable technical knowledge to copy the plans in an
effective way."

"But I suppose either Sir James, or you, or West has that technical
knowledge?"

"No doubt we had, but I beg you won't try to drag me into the matter,
Mr. Holmes. What is the use of our speculating in this way when the
original plans were actually found on West?"

"Well, it is certainly singular that he should run the risk of taking
originals if he could safely have taken copies, which would have
equally served his turn."

"Singular, no doubt--and yet he did so."

"Every inquiry in this case reveals something inexplicable. Now there
are three papers still missing. They are, as I understand, the vital
ones."

"Yes, that is so."

"Do you mean to say that anyone holding these three papers, and without
the seven others, could construct a Bruce-Partington submarine?"

"I reported to that effect to the Admiralty. But to-day I have been
over the drawings again, and I am not so sure of it. The double valves
with the automatic self-adjusting slots are drawn in one of