sentimental effusions remained. It was just a sheet of notepaper
which had accidentally fallen into a basin of water.

"That's all right," said Hillyard; and Fairbairn gently slid the sheet
into the dish in front of Hillyard. And for a while nothing happened.

"It's a clever trick, isn't it?" Hillyard used the words again, but now
with a note of nervousness. "No unlikely paraphernalia needed. Just a
copying pencil and some vinegar, which you can get anywhere. Yes, it's a
clever trick!"

"If it works," Fairbairn added bluntly.

Both men watched the dish anxiously. The paper remained blank. The
solution did not seem to work. It was the first time they had ever made
use of it. The coast slid by unnoticed.

"Lopez was certain," said Fairbairn, "quite certain that this was the
developing formula."

Hillyard nodded gloomily, but he did not remove his eyes from that
irresponsive sheet.

"There may be some other ingredient, something kept quite
secret--something known only to one man or two."

He sat down, hooking his chair with his foot nearer to the table.

"We must wait."

"That's all there is to be done," said Fairbairn, and they waited; and
they waited. They had no idea, even if the formula should work, whether
the writing would flash up suddenly like an over-exposed photographic
plate, or emerge shyly and reluctantly letter by letter, word by word.
Then, without a word spoken, Fairbairn's finger pointed. A brown stain
showed on the whiteness of the paper--just a stroke. It was followed by
a curve and another stroke. Hillyard swiftly turned the oblong
developing dish so that the side of it, and not the end, was towards him
now.

"The writing is across the sheet," he said, and then with a cry, "Look!"

A word was coming out clear, writing itself unmistakably in the middle
of the line, at the bottom of the sheet--a signature. Zimmermann!

"From the General Staff!" said Hillyard, in a whisper of excitement. "My
word!" He looked at Fairbairn with an eager smile of gratitude. "It's
your doing that we have got this--yours and Lopez Baeza's!"

Miraculously the brown strokes and curves and dots and flourishes
trooped out of nothing, and fell in like sections and platoons and
companies with their due space between them, some quick and trim, some
rather slovenly in their aspect, some loitering; but in the end the
battalion of words stood to attention, dressed for inspection. The brown
had turned black before Hillya