Then he took up his own proof, and found the page, and worked it again by his own method: first correction, second correction, third.
He looked out the third correction, and wrote it down. A plus sign. Forty-one miles from the bank.
His hand stopped on the board.
For a long moment he stood looking at the two results: twenty-seven miles and forty-one. Then, very deliberately, he rubbed out the plus with his thumb and wrote a minus in its place, and carried the work down again, and arrived at twenty-eight.
He put the chalk on the ledge and turned to face the room.
Judith had thought, in the three nights she had lain awake, of many things he might do. She had thought he might bluster; she had thought he might blame his computers; she had thought, most likely of all, that he would say something gracious and empty about the uncertainties of observation at sea, and sit down, and let the Board quietly bury the matter. She had not thought that he would look as he did look now: an old man, suddenly, standing very straight in his gown, with chalk on his thumb.
"Gentlemen," said Sir Augustus Threlkeld. "Dr. Wray. Mr. Carrow." His voice was quite steady. "It is quite an error."
The room was entirely silent.
"It is my error," he went on. "Not my computers'. I computed the third table myself, in the winter of the year six, by logarithms, at night, and I never carried the sign. I have had it in my hand eleven years and never once looked. The young lady is right in every particular. The tables are to be withdrawn from the printer this afternoon, and not issued until the third table is corrected and the whole of it examined." He paused. "By a competent computer. I should be obliged, Dr. Wray, if the Board would recommend one to me."
Dr. Wray's walnut face creased very slowly into a smile.
"I think," he said, "that the Board might know of one."
* * *
Afterwards, in the confusion of the emptying theatre, with people crowding round the table and Mr. Carrow talking very fast to the President about the Admiralty's entire confidence in the Board, Sir Augustus came to the front bench where Judith was sitting.
He stood before her for a moment. Then he bowed: not the bow he had given the gallery, but a short stiff bow, as a man bows to another man across a table.