There was little sleeping that night in Johnny Thompson’s tent at the back of his booth, at the “Greatest of all Carnivals.” True, Johnny remained in the tent to doze off at times. Drew Lane and his partner spent their time in scouting about searching for clues that might lead them to the whereabouts of Greasy Thumb and his gang.  
Once, while Johnny was alone, he drew the roll of bills from his pocket.
 
“What am I to do with these?” he asked himself. “Give them to that truck farmer? Simple enough. But where is he? Where does he live?”
 
He examined the bills closely, then let out a low whistle. Two of them were marked with a faint red cross in the corner.
 
57
“Marked money!” he exclaimed in a low tone. “Bad business! Dangerous! Like to throw them away.”
 
Yet, because this roll represented a fairly large sum of money, he did not obey that impulse. Instead, he thrust them once more into his pocket.
 
Half an hour later, having returned from one more fruitless search, Drew and Tom were about to join Johnny in a steaming cup of coffee when, without ceremony, a curious individual crept into the tent.
 
At sight of him Johnny started back. A very small man, with a long sharp nose and piercing yellow eyes, he might have been said to crawl rather than walk.
 
“It’s all right,” Drew assured Johnny. “Meet the Ferret. He is one of us. Very much so.”
 
“Hello, Ferret,” he greeted the newcomer. “What’s up?”
 
The man did not reply at once. Instead, he put out a hand for a cup of the scalding coffee, placed it to his lips and drained it without a pause.
 
58
“Hot stuff!” muttered Johnny.
 
“Very hot!” agreed Drew.
 
The dog has been named man’s best friend. Yet as a hunter he has his handicaps. True, he is a swift runner and can make a great noise. Often by sheer bluff he drives the coyote from the hen roost. Then, too, he can dig. At times he drags a rat from his den and destroys him.
 
The cat has his good points also. He is sly, patient. For hours he waits beside some enemy’s trail until the great moment comes. Then one swift spring, a cry of surprise and pain, and all is over.
 
Yet dog and cat alike are powerless before the sly, deep-digging weasel, the mink and the skunk. Only one crafty, half tamed pet of mankind can cope with these. The ferret with his slim, snake-like body, his beady eyes, his prying nose, glides noiselessly into the deepest burrows and sends its denizens rushing from their dark haunts into sunshine and death.
 
59
So, too, in the ranks of mankind the ferret is to be found. Lacking in physical strength and prowess, yet endowed with a faculty for discovering hidden dens, the human ferret is ever closely associated with the police. He wears neither badge nor uniform. His name is not on the pay roll. Despised by some, he is feared by many. For it is he who many times brings the evil doer to justice.
 
The strange person who crept into Johnny’s tent was of this sort. Indeed, so definitely had his vocation been chosen for him by nature that he was known only as “The Ferret.” If he had any other name it had been forgotten.
 
“The Ferret” had one great redeeming quality. He was a sincere friend of justice. He furnished information only to those who made an honest attempt to enforce the law. He was possessed of an uncanny power. He appeared to read men’s minds. Was an officer a traitor to the cause he had sworn to serve? “The Ferret” knew it on the instant. No information was forthcoming to such a one. Indeed, if he did not watch his step he was likely to feel “The Ferret’s” bite.
 
60
The source of his income was not known. Some rumors had it that a rich philanthropist, realizing his value to the community, had endowed him for life. Another was that he was rich in his own name, that he owned a flat building, stocks, bonds and mortgages, and that his occupation was but a hobby. Strange hobby, you will say; yet there have been stranger, and far less useful.
 
Because they were honest, sincere and fearless, Drew and Howe were ever in “The Ferret’s” favor.
 
Drew Lane’s eyes were alight as they fell upon the insignificant form of “The Ferret.”
 
“What’s up?” he demanded once more.
 
“Mailplane brought down and robbed ten miles from here.” “The Ferret’s” voice was low and soft.
 
How could “The Ferret” know this so quickly? Who can say? The source of his information must have been of an obscure nature. For when Drew pressed him for details he could furnish none. Nor could he tell whether Greasy Thumb had a hand in it.
 
61
“But what’s so valuable in the Air Mail?” Johnny asked. “I thought that was for the most part personal messages, important to the sender, but worthless to others.”
 
“For the most part, yes,” Drew agreed. “But think of the emergencies the Air Mail is prepared to meet. A big deal in stocks is on. The actual securities must be delivered within twenty-four hours. The Air Mail brings them. Mrs. Jones-Smith-Walker, the millionaire widow, arrives in Chicago only to find that a great reception has been planned for her at the country home of her bosom friends, Mrs. Burns-Walker. Her jewels, a hundred thousand dollars’ worth or more, are in New York. Without them she will not be properly dressed. The Air Mail brings them. And who knows but that, through some secret channels the powerful, sometimes rich, sometimes poor, gang that is forever preying upon the foolish rich society folks are tipped off in advance regarding the consignment. Worth going after. What? If you don’t care for the law and have little fear of prison.
 
62
“Mind,” he added, “I don’t say this is the case. I have no information which would even lead me to suspect such a thing.
 
“Only one fact stands out clearly!” he exclaimed, springing into action. “The trail leads to the city. Big affairs may be pulled off by crooks in the country at times. But they always speed away to the city afterward. For it is there that they may most effectually lose themselves.
 
“Come. Let’s be moving. We will find Greasy Thumb in the city.”
 
“I wonder if we will,” Johnny murmured to himself, as he began a hasty pack-up of his personal effects preparatory to leaving his spindle wheel and many baskets of groceries to anyone who chose to take them over on the morrow.
 
63
“The city,” he murmured after a time, “the strangest, weirdest, most fascinating, most beautiful, most dangerous place man has ever known. In the jungle the tiger slinks away from man. There you may sleep in peace. On the polar waste the great white bear floats by on his palace of ice. He will not molest you. In the Rockies where the grizzly roams and the mountain lion inhabits the treetops you are safe. But the city? Oh, well, perhaps you are safe enough there. Who knows?
 
“Good-bye,” he whispered back as he left his booth, “good-bye, old carnival. Good-bye, big-noise-about-nothing. Good-bye, screaming women. Good-bye, laughing children. We’re here to-day and away to-morrow.” He choked a little over these last words. This strange life, the carnival spirit, had got under his skin. Gladly he would have remained. But duty called. “Good-bye, good-bye. We’re here to-day and away to-morrow. The city beckons. We must go.”
 
Settled on the cushions on the back seat of a high-powered police car driven by Drew Lane, Johnny Thompson had time for a few sober reflections.
 
64
As you know from reading The Arrow of Fire, Johnny’s latest venture was in the field of police detection. Many tales Johnny had read of shrewd private detectives who outwitted clever criminals and showed up the stupidity of the police. Johnny had found it difficult to believe that all police detectives were stupid. By contact with four men, Herman McCarthey, Newton Mills, Drew Lane and Tom Howe, he had come to know that men with keen minds and sturdy bodies were more and more offering their services to the police departments of their cities.
 
“No better detective ever lived than Drew Lane,” a reporter had once said to Johnny. And Johnny had found this to be true. He gave himself over with genuine abandon to the business of being Drew Lane’s understudy.
 
Yet, at this moment he found himself missing certain friends who had added joy and inspiration to his life. In a great city friends come and go quickly. Herman McCarthey had retired from active service.
 
“And Newton Mills,” he grumbled to himself. “Where is he?”
 
Where indeed? Johnny had once lifted this shadow of a great detective out from a living hell of remorse and drink and had set him doing marvelous things for the law again.
 
65
“But now he is gone,” he mourned. “I wonder if drink has claimed him. Or is he dead?
 
“Hardly dead,” he corrected himself. “Men, like wounded fish, come to the surface to die. Had he died I would have known it.”
 
Strangely enough, at this moment he thought once more of that spectre-like individual, the Gray Shadow, that had three times crossed his path and three times vanished.
 
“Unusual sort of person, if it be a person,” he said to himself. “Always appears when I am in more or less danger. If I believed in the return of the spirits of the dead I’d say it was the spirit of some dead friend set to guard me.”
 
And Joyce Mills, that daring daughter of a famous father, you will recall her. Johnny, too, recalled her with a sigh.
 
Some people he found it difficult to understand. Joyce Mills was one of these. Once she had inspired him. Now she had gone into the humdrum business of selling books in a department store.
 
66
“At least that’s what she was doing when I saw her last. Queer business for a girl like that,” he grumbled.
 
And yet, as he recollected his last meeting with her, he seemed again to detect a mysterious twinkle in her eyes which appeared to say: “You don’t know all; nor even half.”
 
“Odd sort of girl,” he said to himself. “Have to look her up.”
 
But here we are nearing the city and a new day.
 
“Turn, turn my wheel,
All things must change
To something new,
To something strange.
The wind blows east,
The wind blows west,
The blue eggs in the robin’s nest
Will soon have wings
And beaks and breasts,
And flutter and fly away;
To-morrow be to-day.”
67
So much for the thoughts of Johnny Thompson. He expressed himself in verse at times. Not so, Drew Lane. His thoughts were of a grim and practical sort.
 
“Tom,” he said, speaking to his companion and pal, “Tom, old boy, if we see Greasy Thumb and his pardner, Three Fingers Barbinelle, we’ll arrest them on sight.”
 
“And arrange a case against them later,” agreed Tom.
 
“Hold them on a vagrancy charge. Or more than likely we’ll find them carrying guns.”
 
“Almost sure to.”
 
“Then,” Johnny broke in, “you’ll need to be quick.”
 
“Son,” replied Drew with a drawl, “In this sort of work there are but two classes of people, ‘the quick and the dead.’”