e piazza, crept stealthily along in
the soft light of the moon, until he reached the library window.
There he stopped and listened. All was still within--so still that
the beating of his heart seemed like the hammering of a sledge upon
an anvil by contrast. Then, raising himself cautiously upon his
toes, he peered through the window into the room, the greater part
of which was made visible by the wealth of the moon's light
streaming into it.

"Humph!" said Thaddeus, after he had directed his searching gaze
into every corner. "There isn't anybody there at all. Most
incomprehensible thing I ever heard of."

Rising, he walked back to the piazza door, and went thence boldly
into the library and lit the gas. His piazza observations were then
verified, for the room was devoid of life, save for Thaddeus's own
presence; but upon the floor before the hearth was a broom, and
there were evidences also that the sweeping sounds he had heard had
been caused by no less an instrument than this, for in the corner of
the fireplace was a heap of dust, cigar ashes, and scraps of paper,
which Thaddeus remembered had been upon the hearth in greater or
less quantity when he had turned out the gas to retire a few hours
before.

"This is a serious matter," he said to himself. "Something is
wrong, and I doubt if there have been burglars in the house; but I
can ascertain that without trouble. If the doors and windows are
all secure the trouble is internal."

Every accessible door and window on the basement and first floor was
examined, and, with the exception of the piazza door, which Thaddeus
remembered to have unlocked himself a few minutes before, every lock
was fastened. The disturbance had come from within.

"And Bess must never know it," said he; "it would worry her to
death." And then came a thought to Thaddeus's mind that almost
stopped the beating of his heart. "Unless she has discovered it in
my absence," he gasped. In an instant he was mounting the stairs to
hasten to Bessie's side, as though some terrible thing were pursuing
him.

"Well, what was it, Ted?" she asked, as he entered the room.

Perkins gave a sigh of relief. All was safe enough above-stairs at
least.

"Nothing much," said Thaddeus, in a moment. "There is no one
below."

"But what could it have been?"

"I haven't the slightest idea," said Thaddeus, "unless it was a
stray cat in the house. The sweeping sound may have been caused by
a cat scrat