“Let me carry that suitcase,” I volunteered.

We trudged along across the park, my load getting heavier at every step.

“I’m not surprised at your being winded,” I panted, soon finding myself in the same condition.  “What’s in this—­lead?”

“Something that we may need or may not,” Garrick answered enigmatically, as we stopped in the shadow to rest.

He carefully took an automatic revolver from an inside pocket and stowed it where it would be handy, in his coat.

We resumed our walk and at last had come nearly up to the house on the first floor of which the maid Lucille was.  The suitcase was engaging all my attention, as I shifted it from one hand to the other.  Not so Garrick, however.  He was looking keenly about us.

“Gad, I must be seeing things to-night!” he exclaimed, his eyes fixed on a figure slouching along, his hat pulled down over his eyes, passing just about opposite us on the other side of the street.  I looked also in the gathering dusk.  The figure had something indefinably familiar about it, but a moment later it was gone, having turned the corner.

Garrick shook his head.  “No,” he said half to himself, “it couldn’t have been.  Don’t stop, Tom.  We mustn’t do anything to rouse suspicion, now.”

We came a moment later to the flat-house through the hall of which we had reached the roof that morning and in the excitement of the adventure I forgot, for the time, the mysterious figure across the street, which had attracted Garrick’s attention.

Again, we managed to elude the tenants, though it was harder in the early evening than it had been in the daytime.  However, we reached the roof apparently unobserved.  There at least, now that it was dark, we felt comparatively safe.  No one was likely to disturb us there, provided we made no noise.

Unwrapping the smaller, paper-covered package, Garrick quickly attached the wires, as he had left them, to another cedar box, like that which he had already let down the chimney up the street.

I now had a chance to examine it more closely under the light of Garrick’s little electric bull’s-eye.  I was surprised to find that it resembled one of the instruments we had used down in the room in the Old Tavern.

It was oblong, with a sort of black disc fixed to the top.  In the face of the box, just as in the other we had used, were two little square holes, with sides also of cedar, converging inward, making a pair of little quadrangular pyramidal holes which seemed to end in a small round black circle in the interior, small end.

I said nothing, but I could see that it was a new form, to all intents and purposes, of the detectaphone which we had already used.

The minutes that followed seemed like hours, as we waited, not daring to talk lest we should attract attention.

I wondered whether Miss Winslow would come after all, or, if she did, whether she would come alone.