"That also sounds a good argument," said Quarles, "but is it? He could not deny that he and his wife quarreled rather badly at times, but he wanted to justify his position, and he felt confident the opinion of the doctors would stand, no matter what he might say. If no other facts come to light, suicide will be the line of defense, Wigan, and it will be exceedingly hard to get any judge and jury to convict him. Nothing carries greater weight than medical evidence, and you will find the doctors sticking to their opinion no matter what happens. No, Wigan, your reasons do not prove that he is not an exceedingly clever and calculating rascal. On the present evidence I think he would escape the hangman, but the public will continue to think him guilty unless some one else stands in the dock in his place." "I wonder whether the Folliotts have told the truth," said Zena. "Intuition, Wigan," laughed Quarles, "jumps to the end of the journey and wants to argue backwards." "Do you not often do the same, dear?" "Perhaps, but not this time. I think you said the taxi had been in charge of the police?" "Yes," I answered. "I should like to see it." "We can go to-morrow." I had already spent a couple of hours with that taxi, and I was rather anxious to see how Quarles would go to work with it. He began with the metal work and the lamps, nodded his admiration at the way they were kept, and remarked that but for the vehicle number and the registering machine it might be a private car. He examined the engine and the tires, using his lens; seemed to be particularly interested in the texture of the rubber, and picked out some grains of soil which had stuck in the tire. All four tires came in for this close inspection. Inside the taxi his lens went slowly over every inch of the upholstering, and with the blade of a penknife he scraped up some soil from the carpet. This he put on a piece of white paper and spent a long time investigating it. He opened and shut the door half a dozen times, and shook his head. Then he seated himself in the driver's seat, and in pantomime drove the car for a few moments. Afterwards, he stood back and regarded the car as a whole. "Well, Wigan, it is a very good taxi; let us go and have a ride in another one." He did not hail the first we encountered, and when he did call one it was for the sake of the driver, I fancy. He explained that he wanted to drive to Richmond Green by Hammersmith and Kew Bridge. "And we don't want to go too fast," said Quarles. "Don't you be afraid, guv'nor, I shan't run you into anything; you won't come to no harm with me." "It isn't that," said Quarles, "but I'm out to enjoy myself. I'll add a good bit to what that clock thing says at the end of the run." "Thank you, guv'nor." "Now just get down and open this thing to let me have a look at the works." The driver looked at me, and I nodded. No doubt he thought I was the old man's keeper. Quarles looked at the engine.