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.