d it be that Brent and Flint were drinking? He dared not betray a
fear to Eva. Instead he knocked.

At that moment he could hear the sound of some heavy body falling; then
more laughter as Brent in his hysteria struck the model of the automaton
to the floor.

With the model, unnoticed by Brent, now fluttered to the floor the
letter he had been writing. But the madman paid no attention to that now
as it sifted through the air and fluttered under the sideboard.

"Mr. Brent," called Locke, "please open the door."

Instead of an answer came a loud and insulting laugh, followed by an
incoherent mouthing of words. Eva looked startled, blanched. It was so
unlike her father. For the moment Locke was piqued. But he tried not to
show it as he turned away from the door.

"I am your father's employe," he said, sadly, "and it is his privilege,
I suppose, to laugh at me." He hesitated.

"Oh, but, Quentin--Mr. Locke--I'm--I'm so sorry. Surely he could not
have meant it."

At the head of the stairs Locke tried to smile.

"Don't worry," he said, repressing his feelings. "It will make no
difference between us. Good night."

They parted, Eva closing her door for a sleepless night, Locke to work
far into the night in his laboratory until sheer exhaustion overcame his
feelings.

Meanwhile, in the dining-room, the two men kept terrible vigil, hour
after hour, oblivious of time, in wild and wanton laughter--maniacal
abandon.

A terrible blow had been struck and Reason was tottering on her throne.

Two men had been stricken by an unknown hand--stark, stark mad.

CHAPTER V

"Father--please--open the door!"

It was early the following morning that the butler with frightened face
had called Eva Brent to tell her that her father and Flint had been
locked in the dining-room all night and were still laughing madly.

Eva had hurried down-stairs, encountering Zita as she ran. It was true.
She could hear the voices inside. Nor could she get any answer from the
two men.

"Oh--Zita--please--can't something be _done_?" Eva implored.

With a hasty word Zita hurried away just as Herbert Balcom himself
entered the house from the street.

In utter surprise Balcom nodded at Zita as she poured forth the story of
what had been discovered in the morning, then pushed past her in high
excitement.

"What's wrong?" he asked as he came upon the butler and Eva still
knocking excitedly at the dining-room door.

Eva was almost in a panic