"Well, there was a disagreement. What it was I don't quite know, but in the first place it had some connection with some of Mason's experiments—something which Lawson declined to help him with for professional reasons, or else something he declined to do for Lawson, I don't know which. But the thing went further, for, as a matter of fact, there was something between the young people—Lawson is only twenty-eight—and Mason put an end to that. It had been something like a formal engagement, I think, but in the quarrel—Mason was always quarrelling with somebody when he had friends, and that's why he has so few now—in the quarrel things were said that ended in a rupture. Whether young Lawson was fortune-hunting or not I cannot say, but Mason certainly accused him of it, and promised to keep back the girl's money as long as he could. In the meantime Mason declared an end to the engagement, and poor Helen was broken-hearted; for as I have said, she is an affectionate girl, and she hadn't a friend to confide in. But I'm boring you—you don't want to know all these things, surely?"
"On the contrary, I can't possibly know too much, and the particulars can't possibly be too minute. Nine cases out of ten I bring to an issue by means of a triviality. You were saying a little while back that there were almost no visitors at Mr. Mason's house; but you said 'almost,' and that means there are some. Who are they?"
"Very occasionally—rarely, in fact—there are one or two members of learned societies with whom he had been in correspondence, or who are old friends. There is a Professor Hutton and a Dr. Burge, I believe; but they don't appear once in six months; and there is Mr. Everard Myatt, who is more frequent. He does not profess to be a great man of science, but he is interested in chemistry as an amateur, and is, I fancy, a sort of disciple of Mason's. He has noticed a sad difference in Mason just lately, and he even called on me yesterday, though I hardly knew him by sight, in the hope that I would back up his urgent suggestion that Mason should go off for a change and a rest. Beyond these I don't think I know of a single visitor. But here we are at the Megatherium."
II
Mr. Jacob Mason's house stood in its own grounds in a quiet suburban road. It was not a very large house, but it straggled about comfortably in the manner of detached houses built in the suburbs at a time when space was less valuable than now, and it consisted of two floors only. The front door was not far from the road, and was clearly visible to passengers who might chance to look through either of the two iron gates that opened one on each end of the semi-circular drive.
All these things Martin Hewitt noticed as the Rev. Mr. Potswood pushed open one of these gates, and the two walked up the drive. The front door stood in a portico, and a French window gave access to the roof of this portico from a bedroom or dressing-room. As Hewitt and his companion approached the house the French window was pushed open, and a man appeared—a middle-aged, slightly stoutish man with a short, grey beard; commonplace enough in himself, but now convulsed with noisy anger, shaking his fists and stamping on the portico-roof.
"Get out!" he shouted. "Don't come near my house again, or I'll have you flung out! Go away and take your friends with you! D'you hear? Go away, sir, and don't come here annoying me! Go! Go at once!"
Mr. Potswood absolutely staggered with amazement. "Why," he gasped, "it's Mason! He's mad—clean mad! Why, Mason, my poor friend, don't you know me?"
"Get out, I say!" cried Mason. "Give me no more of your talk! I won't have you here!" And now Hewitt caught a glimpse of a girl's face at the window behind the man—a pale and handsome face, drawn with anxiety and fear.