Nevertheless, Whyland determined to make a very thorough investigation into Mr. Copperdock’s habits and associates. He was rewarded by the discovery of two very interesting facts. A representative of Scotland Yard, announcing himself as an agent of the Planet Typewriter Company, the manufacturers of the machine owned by Mr. Copperdock, and used by his son for writing business letters, called at the tobacconist’s shop, ostensibly for the purpose of inspecting the machine. He succeeded in carrying away with him a specimen of its work, which was submitted to experts. They reported that, although there were no perceptible peculiarities in any of the letters which would enable them to identify this specimen with the address on the envelope sent to Richard Pargent, there was, on the other hand no discrepancy between the two types, and that therefore the envelope might well have been typed on Mr. Copperdock’s machine.