“Yes, plenty of ice,” sneered Vaux.  “I wish she’d bring us a hod or two of coal.”

The wintry landscape of the Park discouraged him profoundly.

“A man’s an ass to linger anywhere north of the equator,” he grumbled.  “Dickybirds have more sense.”  And again he thought of the wood fire in the club and the partly empty but steaming glass, and the aroma it had wafted toward him; and the temperature it must have imparted to “Bill.”

He was immersed in arctic gloom when at length the car stopped.  A butler admitted him to a brown-stone house, the steps of which had been thoughtfully strewn with furnace cinders.

“Miss Erith?”

“Yes, sir.”

“Announce Mr. Vaux, partly frozen.”

“The library, if you please, sir,” murmured the butler, taking hat and coat.

So Vaux went up stairs with the liveliness of a crippled spider, and Miss Erith came from a glowing fireside to welcome him, giving him a firm and slender hand.

“You are cold,” she said.  “I’m so sorry to have disturbed you this evening.”

He said: 

“Hum—­hum—­very kind—­m’sure—­hum—­hum!”

There were two deep armchairs before the blaze; Miss Erith took one, Vaux collapsed upon the other.

She was disturbingly pretty in her evening gown.  There were cigarettes on a little table at his elbow, and he lighted one at her suggestion and puffed feebly.

“Which?” she inquired smilingly.

He understood:  “Irish, please.”

“Hot?”

“Thank you, yes,”

When the butler had brought it, the young man began to regret the Racquet Club less violently.

“It’s horribly cold out,” he said.  “There’s scarcely a soul on the streets.”

She nodded brightly: 

“It’s a wonderful night for what we have to do.  And I don’t mind the cold very much.”

“Are you proposing to go out?” he asked, alarmed.

“Why, yes.  You don’t mind, do you?”

“Am I to go, too?”

“Certainly.  You gave me only twenty-four hours, and I can’t do it alone in that time.”

He said nothing, but his thoughts concentrated upon a single unprintable word.

“What have you done with the original Lauffer letter, Mr. Vaux?” she inquired rather nervously.

“The usual.  No invisible ink had been used; nothing microscopic.  There was nothing on the letter or envelope, either, except what we saw.”

The girl nodded.  On a large table behind her chair lay a portfolio.  She turned, drew it toward her, and lifted it into her lap.

“What have you discovered?” he inquired politely, basking in the grateful warmth of the fire.

“Nothing.  The cipher is, as I feared, purely arbitrary.  It’s exasperating, isn’t it?”

He nodded, toasting his shins.