like the faces of the men who now stole by me in their felted footwear
with a cat-like tread.

At a cross street I turned and came upon a small group of shops with
monotonous panelled display windows inserted in the concrete walls. Here
I found my tailor and going in I promptly laid down his notice and my
clothing card. He glanced casually at the papers, punched the card and
then looking up he remarked that my new suit had been waiting some time.
I began explaining the incident in the mine and the stay in the
hospital; but the tailor was either disinterested or did not comprehend.

"Will you try on your new suit now?" he interrupted, holding forth the
garments. The suit proved a trifle tight about the hips, but I hastened
to assure the tailor that the fit was perfect. I removed it and watched
him do it up in a parcel, open a wall closet, call my house number, and
send my suit on its way through one of the numerous carriers that
interlaced the city.

As I walked more leisurely back to my apartment by a less direct way, I
found my analytical brain puzzling over the refreshing quality of the
breezes that blew through those tunnel-like streets. With bits of paper
I traced the air flow from the latticed faces of the elevator shafts to
the ventilating gratings of the enclosed apartments, and concluded that
there must be other shafts to the rear of the apartments for its exit.
It occurred to me that it must take an enormous system of ventilating
fans to keep this air in motion, and then I remembered the liquid air
engine I had seen in the mine, and a realization of the economy and
efficiency of the whole scheme dawned upon me. The Germans had solved
the power problem by using the heat of the deeper strata of the earth to
generate power through the agency of liquid air and the exhaust from