"I? Not to anything. I never troubled myself to think about it."
The learned gentleman rubbed his hands with satisfaction. "What you acknowledge is so true to nature, colonel! Those who, like you, are affected with colour-blindness, can rarely be brought to believe in their own defect. It is a fact that the greater portion of them are not conscious of it; they really don't know that they cannot distinguish colours. Some few have perhaps a dim idea that they are not so quick in that particular as others, but they never think of questioning the cause. To use your own expression, it does not trouble them. I understand you maintain that on the night of the accident the usual light was up--green?"
"Yes," said the colonel. "They exhibit the green light always at Coombe Dalton station, to enforce caution, on account of the nasty turning just after passing it. I maintain, as you say, that the customary green light was shown that night."
"Now I will tell you how to account for that belief;" said the professor. "It was not so much that you could be sure the green light was up, as that you could not distinguish any difference between the one you saw, and the one you were accustomed to see. You could not discern the difference, I say, and therefore you maintained it to be, as you believed, the same one--the green."
"This seems plausible enough, as you state it," acknowledged Colonel West, at length. "But pray why should it not be my young friend, Jupp, who was mistaken--and not I?"
The professor shook his head. "I am quite sure that this gentleman"--indicating Oliver Jupp--"can never be mistaken in colours or in their shades, so long as he retains his eyesight to see anything: he has the organ very largely developed. I am right, colonel," he added, nodding.
"But what do you say to Cooper, the driver?" returned the colonel. "He says the light was green: and everybody agrees that he would only assert what was true."
"What he thought was true," corrected Dr. Macpherson. "There is little doubt, in my mind, that Cooper's case will turn out to be like your own--a fact of colour-blindness. He could not distinguish the difference in the light from the ordinary light, and therefore believed it to be the same."
"Both of us blind!" exclaimed the colonel, with wide-open eyes. "That would be too good, Mr. Professor."
"I said only colour-blind," corrected the professor. "There is not the least doubt that it will turn out to be so."