“I don’t intend to work it out,” I said irritably. “But I mean to use motion as a translator of the time, which is 1:30 in the morning, to take me to a certain space, which is where I live.”

But as it happened, I did not go into my house when I reached it. I was wide awake, and I perceived, on looking up at my wife’s windows, that the lights were out. As it is her custom to wait up for me on those rare occasions when I spend an evening away from home, I surmised that she was comfortably asleep, and made my way to the pharmacy to which the Wellses’ governess had referred.

The night-clerk was in the prescription-room behind the shop. He had fixed himself comfortably on two chairs, with an old table-cover over his knee and a half-empty bottle of sarsaparilla on a wooden box beside him. He did not waken until I spoke to him.

“Sorry to rouse you, Jim,” I said.

He flung off the cover and jumped up, upsetting the bottle, which trickled a stale stream to the floor. “Oh, that’s all right, Mr. Johnson, I wasn’t asleep, anyhow.”

I let that go, and went at once to the object of our visit. Yes, he remembered the governess, knew her, as a matter of fact. The Wellses’ bought a good many things there. Asked as to her telephoning, he thought it was about nine o’clock, maybe earlier. But questioned as to what she had telephoned about, he drew himself up.

“Oh, see here,” he said. “I can’t very well tell you that, can I? This business has got ethics, all sorts of ethics.”

He enlarged on that. The secrets of the city, he maintained loftily, were in the hands of the pharmacies. It was a trust that they kept. “Every trouble from dope to drink, and then some,” he boasted.

When I told him that Arthur Wells was dead his jaw dropped, but there was no more argument in him. He knew very well the number the governess had called.

“She’s done it several times,” he said. “I’ll be frank with you. I got curious after the third evening, and called it myself. You know the trick. I found out it was the Ellingham, house, up State Street.”