<h2 id="id00903" style="margin-top: 4em">CHAPTER XVI</h2>
<h4 id="id00904" style="margin-top: 2em">THE PROFESSOR'S EXPERIMENT</h4>
<p id="id00905">Throughout all this excitement Percy Darrow did absolutely nothing. He
spent all his time, save that required for meals and the shortest
necessary sleep, in a round-armed wooden chair in the wireless station of
the Atlas Building. Jack Warford sat with him. Darrow rarely opened his
mouth for speech, but smoked slowly a few cigarettes, and rolled many
more, which he held unlighted in the corner of his mouth until they
dropped to pieces. He watched quietly all that went on; glanced through
such messages as came in from Monsieur X, read the papers, and dozed. To
reporters he was affable enough in his drawling slow fashion, but had
nothing to say.</p>
<p id="id00906">"Eldridge is doing this," he said to them; "I'm only in the position of an
interested spectator."</p>
<p id="id00907">Eldridge had taken hold in a thoroughly competent way. Back of the cold
precision of his undoubted scientific attainments lurked, unexpected by
most, a strong ambition and a less admirable hankering for the lime-light.
His opportunity to gratify all these appetites—science, advancement, and
fame—was too good not to cause him the deepest satisfaction.</p>
<p id="id00908">"I have determined," he told the reporters, "that this particular
instrument alone receives the messages from the unknown perpetrator. Our
investigations must be initiated, therefore, in this apartment."</p>
<p id="id00909">"How do you explain it?" asked one of the reporters.</p>
<p id="id00910">"I can not explain it scientifically," admitted Eldridge, "but I can
surmise that the fact either purposely or accidentally has to do either
with this instrument's location or with some slight and undetermined
peculiarity of its tuning."</p>
<p id="id00911">"You could easily tell which by moving the instrument to another station
where they aren't getting the messages now," suggested Darrow lazily.</p>
<p id="id00912">"Certainly," snapped Eldridge, "any child could deduce that. But I fail to
see the use or necessity for the determination at all unless in a spirit
of frivolous play. Our task is not to discover where the messages can be
received, but whence they are sent."</p>
<p id="id00913">He gazed frostily at the man who had interrupted him. Darrow smiled softly
back.</p>
<p id="id00914">"How far will your instrument carry in sending?" Eldridge asked Simmons.</p>
<p id="id00915">"Its extreme is about two hundred miles."</p>
<p id="id00916">"Then we can safely assume that a circle drawn with a two-hundred-mile
radius would contain this man you call Monsieur X"—the newspapers had
adopted Darrow's nickname for the Unknown—"since you have succeeded in
communicating with him."</p>
<p id="id00917">"Marvelous," said Darrow to Jack—but under his breath.</p>
<p id="id00918">"As the sending of Monsieur X is faint, it follows that he is somewhere
near the periphery of this circle, or that he is possessed of a primitive
or weak instrument. By the doctrine of probabilities we should be
justified in concluding against the latter supposition."</p>
<p id="id00919">"How's that, Professor?" asked the <i>Morning Register</i> man. "It doesn't get
to me."</p>
<p id="id00920">"He is evidently a man not only of scientific attainments, but of immense
scientific possessions—as is evidenced by these phenomenal results he is
able to accomplish. But we are not justified in reasoning according to the
doctrine of probabilities. Therefore, we shall proceed methodically. I
have already made my preparations."</p>
<p id="id00921">Eldridge looked about him with an air of triumph.</p>
<p id="id00922">"I am fortunate enough to have, in the present crisis, unlimited financial
backing," he said. "Therefore, I am in a position to carry out the most
exhaustive of experiments."</p>
<p id="id00923">He stretched his hand out for a long roll, which he laid flat upon the
table, pinning down the corners.</p>
<p id="id00924">"Here is a map of the Eastern States," said he. "I have drawn a circle on
it with a two-hundred-miles radius. At this moment a private instrument
with a full crew to string sending and receiving wires is two hundred
miles from here on the New York Central Railroad. It has for its
transportation a private train, and it will be given a clear right of
way." He turned to Simmons. "Have you found yourself able to communicate
with this Monsieur X at any time?"</p>
<p id="id00925">"Communicate!" echoed Simmons. "Why, he's easier to talk to than a girl
who wants an ice-cream soda!"</p>
<p id="id00926">"Then send this: 'Your messages have been communicated to the people. Be
patient.'"</p>
<p id="id00927">Simmons touched the key. The spark leaped crashing.</p>
<p id="id00928">"What do you get?" asked Eldridge, after a moment.</p>
<p id="id00929">"Oh, a lot of the same sort of dope," answered Simmons wearily. "Do you
want it?"</p>
<p id="id00930">"No, it is not necessary," replied Eldridge. "But listen for another
message from about the same distance when he has finished."</p>
<p id="id00931">Silence fell on the room. At the end of ten minutes Simmons raised his
head.</p>
<p id="id00932">"I get 'O K Q' over and over," said he. "Want that?"</p>
<p id="id00933">"That," replied Eldridge with satisfaction, "indicates that my crew on the
special train in the Adirondacks two hundred miles away has heard your
message to Monsieur X." He glanced at his watch. "Now, if you would be so
good as to afford me a moment's assistance," he requested Simmons, "I wish
to disconnect from your battery one of your powerful Leyden jars, and to
substitute for it one of weaker voltage. I ventured to instruct my
delivery man to leave a few in the outer hall."</p>
<p id="id00934">"That will weaken the sending power of my instrument," objected Simmons.</p>
<p id="id00935">"Exactly what I wish to do," replied Eldridge.</p>
<p id="id00936">"He's clever all right," Darrow murmured admiringly to Jack. "See what
he's up to?"</p>
<p id="id00937">"Not yet," muttered Jack.</p>
<p id="id00938">The substitution completed, Eldridge again glanced at his watch.</p>
<p id="id00939">"Now," he instructed Simmons, "send the letters 'Q E D,' and continue to
do so until you again hear the letters 'O K Q.'"</p>
<p id="id00940">Simmons set himself to the task. It was a long one. At last he reported
his answer.</p>
<p id="id00941">"He sends 'O K Q ten,'" he said.</p>
<p id="id00942">Eldridge turned to the reporters.</p>
<p id="id00943">"That means that the substitution of the smaller Leyden jar for one of the
larger reduced the sending power of this instrument just ten miles," said
he. "My crew has quite simply moved slowly forward until it caught our
sending here."</p>
<p id="id00944">"Next," he instructed Simmons, "see if you can communicate with Monsieur<br/>
X."<br/></p>
<p id="id00945">The operator speedily reported his success at that. Eldridge removed his
glasses and polished their lenses.</p>
<p id="id00946">"Thus, gentlemen," said he, "from our circle of two-hundred-mile radius we
have eliminated a strip ten miles wide. Naturally if this weakened sending
reaches only one hundred and ninety miles, and our antagonist receives our
messages, he must be nearer than one hundred and ninety miles. We will now
further reduce the strength of our sending and try again."</p>
<p id="id00947">The younger men present broke into a shout,</p>
<p id="id00948">"Good work!" somebody cried. They crowded about, keenly interested in this
new method of man-hunting. Only Darrow, tipped back in his chair against
the wall, seemed unexcited.</p>
<p id="id00949">To Jack's whispered question he shook his head.</p>
<p id="id00950">"It's ingenious," he acknowledged, "but he's on the wrong track." That was
as far as he would explain, and soon dropped into a slight doze.</p>
<p id="id00951">Throughout the greater part of the night the experiment continued. Battery
by battery the sending power of the instrument was weakened. Mile by mile
the special train drew nearer until, by catching the prearranged signal,
it determined just how far the new sending reached. Then Simmons tried
Monsieur X. As the latter invariably answered, it was, of course, evident
that he remained still in the narrowing zone of communication. It was
fascinating work, like the drawing of a huge invisible net.</p>
<p id="id00952">The reporters on the morning papers mastered only with difficulty their
inclination to stay. They had to leave before their papers went to press,
but were back again in an hour, unwilling to lose a moment of the game. A
tension vibrated the little office. Only Percy Darrow dozed alone in the
corner, leaning back in his wooden armchair.</p>
<p id="id00953">At near four o'clock in the morning Simmons raised his head after a long
bout of calling to announce that he could get no reply from Monsieur X.</p>
<p id="id00954">"He's got tired of your fool messages," remarked the <i>Register</i> man. "And<br/>
I don't wonder! Guess he's gone to bed."<br/></p>
<p id="id00955">Eldridge said nothing, but replaced the Leyden jar he had but just
removed.</p>
<p id="id00956">"Try one," said he.</p>
<p id="id00957">"I get him," reported Simmons, after a moment.</p>
<p id="id00958">"Send him anything plausible and reassuring," commanded Eldridge hastily.
He turned to his small and attentive audience in triumph. "Thus,
gentlemen," he announced, "we have proven conclusively that our man is
located between forty and fifty miles from New York. If we draw two
circles, with this building as center, the circumference of one of which
is fifty, the other forty miles away, we define the territory within which
the malefactor in question is to be found."</p>
<p id="id00959">The people in the room crowded close about the table to examine the map
upon which Professor Eldridge had drawn the circles.</p>
<p id="id00960">"There's an awful lot of country—some of it pretty wild," objected the
<i>Bulletin</i> man. "It will be a long job to hunt a man down in that
territory."</p>
<p id="id00961">"Even if it were as extensive a task as a hasty review of the facts might
indicate," stated Eldridge, "I venture to assert that enough men would be
forthcoming to expedite such a search. But modifying circumstances will
lighten the task."</p>
<p id="id00962">"How's that?" asked the <i>Banner</i> man, speaking for the others' evident
interest.</p>
<p id="id00963">"We have no means of surmising the method by which this man succeeds in
arresting vibratory motions of certain wave-lengths," said Eldridge
didactically, "any more than we are able to define the precise nature of
electricity. But, as in the case of electricity, we can observe the action
of its phenomena. Two salient features leap out at us: one is that these
phenomena are limited in time; the other that they are limited in space.
The latter aspect we will examine, if you please, gentlemen.</p>
<p id="id00964">"The phenomena have been directed with great accuracy (a) at the Atlas
Building; (b) at this city and some of its immediate suburbs. The
peculiarity of this can not but strike an observant mind. How is this man
able, at forty or fifty miles distance, to concentrate his efforts on one
comparatively small objective? We can only surmise some system of
insulating screens or focal mirrors. I might remark in passing that the
existence of this power to direct or focus the more rapid ethereal
vibrations would be a discovery of considerable scientific moment. But if
this is the method employed, why do we not cut a band of vibratory
nullifications, rather than touch upon a focal point?"</p>
<p id="id00965">"Repeat softly," murmured the irrepressible <i>Register</i> man.</p>
<p id="id00966">"Why," explained Eldridge patiently, "are not the people and buildings
between here and the unknown operator affected? The only hypothesis we are
justified in working upon is that the man's apparatus is at a height
sufficient to carry over intervening obstacles. This hypothesis is
strengthened by the collateral fact that the territory we have just
determined as that within which he must be found lies in the highlands of
our own and neighboring states. We may, therefore, eliminate the low-lying
districts within our radius."</p>
<p id="id00967">Percy Darrow opened one eye.</p>
<p id="id00968">"Perhaps he's up in a balloon," he drawled languidly; "better take along
an aeroplane."</p>
<p id="id00969">Eldridge cast on him a look of cold scorn. Darrow closed the eye.</p>
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