While the doctor bandaged Hamerly’s head, I signalled a hansom, and in a few minutes we were speeding off to Half-Moon Street.

Too much shaken up by his fall for conversation, Hamerly lay back against the cushions till we reached his lodgings, but he arrived there without seeming any worse for the trip. I saw him safely to bed, promised him an early visit, and left a call for a near-by doctor. Then I looked at my watch. Barely time to reach Dorothy’s train. “To Euston. Rush!” I cried to the cabby, and away we sped. Just as the train came puffing in, I reached the platform, and there was Dorothy’s dear head leaning from the window of her car. The black old station was transformed as she stepped lightly to the platform, followed by her maid. She came towards me with both hands outstretched. “Oh, Jim, it’s good to see you. Where’s Tom?”

“Down at Folkestone,” I answered. “We’ll join him there as soon as you’ve had a night’s sleep.”

“Why wait for that?” asked Dorothy energetically. “It’s only twelve now. We can run down there after lunch. Where are our rooms?”

“At the Savoy,” I said. “Suppose you send your maid up there with the luggage, and we go up in a hansom.”

It took scarcely ten minutes to load the maid and the luggage in a four-wheeler and join Dorothy. As we swung out through the gates, she spoke with a long breath. “It seems good to be back in London again, even with war so near and with so much ahead of us. Now, tell me everything that’s happened since you came over to London from Portsmouth. I got your letter at Queenstown telling about your experiences on the bottom of the sea. How I wish I could have been there. But never mind that now. Tell me all you’ve done in the last four days.”

I settled down to my task. “Tom and I came over safely, as you already know, from our wire at Queenstown. We decided that ‘the man’ would be working in the Channel and, after some discussion, settled on Folkestone as the base from which to work the wave-measuring machine. We took the apparatus down there three days ago, got a big room and set it up. I chartered a yacht.”

“What did you do that for?” interrupted Dorothy.