Captain Shannon by Coulson Kernahan

I had already decided that my next destination must be Stanby, where it would be necessary to pay a visit to Professor Lawrance's hair-cutting establishment. But first I had to read the letters I had secured, so I turned into a small quiet-looking hotel and, having ordered dinner, asked that I might have the use of a bedroom. Then I rang for a jug of boiling water, and on its arrival I dived into the folds of my umbrella, and having brought up the two epistles which were there secreted I proceeded to hold them over the steam until the gum was so moist that it was possible to open them.

The letter for Green was, as I have said, directed to himself in his own writing. It contained nothing more important than a sheet of blank notepaper, which, as the reader will already have surmised, had evidently been sent as a "blind," its purpose being to afford the inquiry agent an excuse for calling at the shop where it had been delivered.