He sat thinking deeply, unconsciously whistling his little tune through his closed teeth. There was another peculiarity about the forged note. The letters were a trifle indented, showing that the typewriter keys had been struck with rather more than the usual force. He turned the sheet over, and he saw that so much was this the case that the stops were punched almost through. Picking up the genuine letters, he looked for the same peculiarity, but the touch in these cases was much lighter and even the full stop barely showed through. This seemed to justify a further deduction—that the writer of the forged note was unskilled, probably an amateur, while that of the others was an expert. French felt he could safely assume that the forged note had been typed by some unauthorised person, using the machine in the London office. But, so far as he could see, these deductions threw no light on the guilt or innocence of Vanderkemp. The letter might have come from some other person in London, or Vanderkemp might have typed it himself during one of his visits to the metropolis. More data was wanted before a conclusion could be reached. Though from what he had seen of Schoofs, the Inspector thought it unlikely that he was mixed up in what he was beginning to believe was a far-reaching conspiracy, he did not mention his discoveries to him, but continued trying to pump him for further information about the missing traveller. Vanderkemp, it seemed, was a tall man, or would have been if he held himself erect, but he had stooped shoulders and a slouching way of walking which detracted from his height. He was inclining to stoutness, and had dark hair and a sallow complexion. His chin was cleanshaven, but he wore a heavy dark moustache. Glasses covered his short-sighted eyes. French obtained some samples of his handwriting, but no photograph of him was available. In fact, Mr. Schoofs did not seem able to supply any further information, nor did an interrogation of the typist and office boy, both of whom spoke a little English, produce any better results. “Where did Mr. Vanderkemp live?” French asked, when he thought he had exhausted the resources of the office.