CHAPTER XXII

IN WHICH A MATTER OF MUCH INGENUITY IS CONSIDERED

“Hello!” said Bat, his eyes almost bulging at the sight. “What the

dickens is that?”

For answer the crime specialist unwound the string, drew another from

the many in Scanlon’s hands, and wrapped it around the blade in turn.

Once more he held up the weapon and now they read:

T

O

N

I

G

H

T

“I get it,” said the big man, “not all, but some. Those packages sent

Miss Hohenlo had nothing at all that was worth looking at _inside_; it

was _outside_ that their interest lay. In the string.”

“I think,” said the girl, wonderingly, “I’ve heard of some such a thing

as this before. But it never occurred to me to apply it in this case.”

“Alva has a wooden sword the exact shape and dimensions of this,” said

Ashton-Kirk, tapping the weapon. “When he desired to send a message

to his confederate in Schwartzberg he’d wrap a string about the stick

and carefully ink his communication, letter after letter, down its

length. After this he’d unwind the cord, tie it about a parcel of

blank paper and dispatch it. There was nothing about it that would

excite suspicion; it held its secret until wrapped around the blade of

the sword; then bit by bit the inked portion fell into place, forming

the letters, and the writing was read.”

“All these strings are messages then,” said Scanlon. He frowned

perplexedly, and asked: “But why write this way? Why not a letter, and

a cipher inside?”

“The letter might, in some way, be opened.”

“But it couldn’t be read.”

“Perhaps not; nevertheless a cipher writing would attract notice, and

in the face of such happenings as Schwartzberg has been experiencing,

suspicion would be sure to follow.”

“That’s right,” said Bat. Then with a nod at the strings: “Going to

read them all?”

“No,” said Ashton-Kirk. “It is hardly worth while.” He threw the heavy

sword upon a table and crossed to the harp once more. “They must be

very brief, and little could be got from them at best. They, for the

most part, merely appointed a time for the real communications.”

“The real ones!”

“Yes; and those were received and answered upon the strings of the

harp.”

Scanlon gazed at the girl, and then his eyes went wonderingly back to

the other. Miss Knowles took an eager forward step.

“How?” she said.

“Upon my first visit,” said Ashton-Kirk, “I knew that you were calling

my attention urgently to this instrument. And, in consequence, I took

especial interest in it. I noted some peculiarities, but I did not

form any conclusions until after I’d had Scanlon’s report of what he’d

witnessed, and had another and specialized examination of its parts a

while ago.

“The harp,” he went on, glancing at his two hearers, “is not, as a

rule, a powerfully made thing. This is especially so in the case of

those of this small size. The wood and the metal that go into its

construction are light.” His keen glance now fixed itself upon Miss

Knowles, and he asked: “Do you know whether this instrument has been

sent away at any time recently for repairs?”

“It has. Shortly after we came here,” she answered. “Something was

broken, I understood.”

Ashton-Kirk nodded.

“The gilding is much newer in some places than it is in others,” said

he. “It’s the sign of the repairer of anything that he never does all

over a job with his finishing tool, merely touching up the parts he’s

worked upon.

“More than likely,” he went on, his eyes now upon the harp, “the

sending of the instrument away was for a reason altogether different

from the one given out. For in those parts where the tinker’s hand is

plainest, I find that some very important and unusual departures have

been made.”

“The upper strings are odd,” said the girl, eagerly. “I often noticed

them. They are of metal.”

“And very heavy--of steel I should say; and they are strung to an

astonishing tension--infinitely higher than the customary strings of

the harp. The ‘pull’ of a number of steel strings of this thickness,

and keyed to this pitch, would be too much for a frame of the ordinary

sort. It would be pulled asunder. Consequently this one has been

powerfully re-inforced; the keys are of a special type, and the sockets

in which they turn appear marvellously strong.”

“But why all this?” asked Scanlon, his frowning gaze upon the harp.

“It was found necessary to establish a means of communication between

the inside of Schwartzberg and the outside. Letters or written messages

would not do; signal lights might be seen; secret meetings were almost

impossible, for one could not often steal successfully in and out of a

place watched as this one is.”

“No,” agreed Scanlon, “it couldn’t be depended on. And neither could

the vaults be used as a meeting place. For the door to them is the most

watched thing in the house.”

“A way must be had,” said Ashton-Kirk, “and one that must be silent and

secret. This man, Alva, as Fuller’s report tells, is an able physicist,

and so the method hit upon of bridging this difficulty must be his.” He

looked at them as though asking their particular attention. “The eye,”

said he, “is capable of vision only up to a certain point. It will

follow an object going up into the air; then the object will disappear;

it is ‘out of sight.’ However, though the object can’t be seen, it is

still there, still going upward.

“You’ve heard the yell of the siren, a thing used upon the seagoing

ships?” he proceeded. “You’ve heard its shriek mount and mount, getting

higher and higher, and finally you ceased to hear it? But it had not

stopped. It was still going on, only it had reached a pitch so high

that it was out of ear-shot. It was only when it began to fall and had

reached the point where you had lost it, that you began to hear it

once more.”

Mr. Scanlon drew down one corner of his mouth and blinked a great

number of times.

“What do you know about that!” said he.

“Perhaps the world’s greatest authority upon sound,” Ashton-Kirk

went on as he took some notes from his pocket-book, “is the German,

Helmholtz. In his book ‘On the Sensations of Tone’ he says:

“‘The simple partial tones contained in a composite mass of musical

tones produce peculiar mechanical effects in nature, altogether

independent of the human ear and its sensations, and altogether

independent of merely theoretical considerations. These effects

consequently give a peculiar objective significance to this peculiar

method of analyzing vibrational forms.’

“Then,” continued Ashton-Kirk, “this master of sound goes on to speak

of the phenomenon of sympathetic resonance. He says on this point:

‘When, for example, the strings of two violins are in exact unison, and

one string is bowed, the other will begin to vibrate.’ And in another

place: ‘Gently touch one of the keys of a pianoforte without striking

the string, so as to raise the damper only, and then sing a note of

the corresponding pitch, forcibly directing the voice against the

strings of the instrument. On ceasing to sing the note will be echoed

back from the piano. It is easy to discover that this echo is caused

by the string which is in unison with the note, for directly the hand

is removed from the key, and the damper is allowed to fall, the echo

ceases.’

“We see, in the case of the siren, and in other things, that some tones

are so high that they are not heard. Also we see, by Helmholtz, that

when a string keyed to a certain tone is struck, another string, keyed

to the same tone, will at once take up the sound, or vibration----”

Here Miss Knowles interrupted him, eagerly.

“I think I see what you mean,” she said. “These unusual strings upon

the harp, this great strengthening of the frame, means that it is keyed

to this inaudible pitch. That some one outside has an instrument of

some sort keyed in unison; and when the harp string is touched, the

other vibrated in sympathy.”

“And that these vibrations, made in long or short waves, or in groups,

much, perhaps, as the telegraph code is made, formed a ready means of

communication.”

Mr. Scanlon seemed appalled.

“Well,” said he, after a short pause, “I think I’ve absorbed the most

of it. But I’m not sure. However, there is one thing I _am_ sure of,

and that is that I’ve got a cabinet sized photograph of the party

who’s got the other instrument. That’s what Alva had that night on the

hilltop when I saw him sitting in the moonlight. He was exchanging

silent talk with Schwartzberg.” Then an idea seemed to strike him, and

he frowned again. “There is one thing that I don’t quite get. And that

is: If these vibrations, or tones, or sounds, whatever you call them,

were too high to be heard, how did the receivers of them make them out?”

Ashton-Kirk shook his head.

“As to that,” said he, “I am not prepared to say just now. A further

search into the thing might bring it out, but I’m not sure. But this I

will say: The sense of touch is marvellously sensitive in some people;

one every now and then hears some wonderful story with regard to it.

Fine, delicate hands may be the answer to your question.”

“Another thing,” said the girl. “Why was the wind required to always

be from the direction of the person sending the vibrations to

Schwartzberg? You’ll say to carry them. But what of the answer to them?

Would not the wind which carried the vibrations from one quarter hold

back those sent from the one opposite?”

“Only in part, unless the wind was very strong. And I think if you

can remember the nights upon which this means of communication was

used, they were fairly calm. The fact that the wind at the time of the

signals was always from the direction of the person outside might be

explained by that person’s superior knowledge of the medium in use.

Having a more perfect understanding of it, he was the more able to read

its fainter manifestations.”

Here a small clock hurriedly struck the hour of nine. And Ashton-Kirk

looked at Scanlon.

“And now,” he added, “I think it’s time to drop speculation for a

space. There is some work ahead of us which is going to be sharp and of

the sort that leaves not even a trace of doubt in the mind.”

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