"That's exactly what I am beginning to think.
We'll soon see if you are right. Make me another disc."

With a pocket rule he measured the diameter of the dollar.
"Practically an inch and a half," he announced, putting down the
figures 1.5 on paper. He multiplied those figures by 3.1416.

"That," said he, pointing to the resulting figures, 4.71+, "represents
the circumference of a dollar. Now we'll divide the circumference by
26, the number of letters in the alphabet."

He performed the division. "Eighteen one-hundredths of an inch," he
announced. "That's practically a scant fifth of an inch. We'll call
it so, anyhow," he continued as he marked off the space on a sheet of
paper with his rule. "Each sector," he said, "gets exactly that amount
of space on the circumference."

He pulled open the drawer of the desk and began to rummage through a
tray full of pens, pencils, and other drawing materials. "I wonder if
there is such a thing as a pair of dividers here," he remarked. And a
moment later he exclaimed "Good!" and drew forth the compasses he was
looking for.

He set his dividers according to the space he had marked off with his
rule, then proceeded to divide the circumference of the new paper disc.
When he had gone completely round the disc, he seized pencil and ruler
and began to draw lines from centre to circumference--the spokes of his
wheel--each spoke running from the dot in the centre to one of the
points indicated by the dividers. When he had finished, the disc was
divided into twenty-six equal sectors, like tiny pieces of a pie.

"We shall soon know whether you are right or not in your guess, Roy,"
said Captain Hardy.

He laid the dollar beside the disc and began to copy on the disc the
marks on the dollar. "We'll put four marks in this sector," he said,
making four dots with his pencil. "They are like those four scratches
here," and he pointed to the four marks in a row on the dollar. "They
must be four T's. At any rate we'll call this the T sector. On the
dollar you notice this row of three scratches--the next sector to the
left of the T sector. You remember we had three O's, three A's, and
three S's. These three scratches must, therefore, be O's, A's, or S's.
Since they are next to the T's, they are doubtless S's. I'll mark the
sector so anyway. That gives us the T sector and the S sector. If we
are on the right track, then the sector to the left of the S space is
the R sector, an