I learnt this incidentally through being interviewed some years ago at a railway station.  A few minutes after the ordeal I found myself close up to my interviewer, when he was re-telling the incident to a brother journalist, who was also eager to find me.  “He is down there, in one of the last carriages of the train.  You will know him at once; he is wearing a green Homburg hat and a red tie, and a black coat.”

Fortunately I had a grey overcoat on my arm, in which was a travelling cap and a comforter.  Diving into the waiting-room, I effected a “quick change” into these, crammed my hat into my pocket, and tottered back, with an invalid shuffle, to my carriage.  I re-entered it under the nose of the waiting reporter without being suspected, and presently had the pleasure of being carried away before him unassailed.

On a recent occasion in my knowledge a man was hunted down into a back street which was a cul-de-sac, with no exit from it.  He turned into the door of a warehouse and went up some flights of stairs, hoping to find a refuge, but, finding none, he turned back and came down again and faced the crowd which was waiting outside, uncertain which house he had entered.

By assuming extreme lameness in one leg, hunching up one shoulder, and jamming his hat down over a distorted-looking face, he was able to limp boldly down among them without one of them suspecting his individuality.

In regard to disguises, hair on the face—­such as moustache or beard—­are very usually resorted to for altering a man’s appearance but these are perfectly useless in the eye of a trained detective unless the eyebrows also are changed in some way.

[Illustration:  Another instance of how an effective disguise can be assumed on the spur of the moment.  This disguise was effected in two minutes.]

[Illustration:  The use of hair in disguising the face is perfectly useless unless the eyebrows are considerably changed.  The brow and the back of the head are also extremely important factors in the art of disguise.

The second picture shows the effect of “improving” the eyebrows of the face on the left, and also of raising the hair on the brow, while the third sketch shows what a difference the addition of a beard and extra hair on the back of the head, can make.]

I remember meeting a man on the veldt in South Africa bronzed and bearded, who came to me and said that he had been at school with one of my name.  As he thrust his hat back on his head I at once recognised the brow which I had last seen at Charterhouse some twenty-five years before, and the name and nickname at once sprang to my lips.  “Why, you are Liar Jones,” I exclaimed.  He said, “My name is Jones, but I was not aware of the ‘Liar.’”

“In altering your face you must remember that ‘improved’ eyebrows alter the expression of the face more than any beards, shaving, etc.  Tattoo marks can be painted on the hands or arms, to be washed off when you change your disguise....  Disguising by beginners is almost invariably overdone in front and not enough behind....  Before attempting to be a spy first set yourself to catch a spy, and thus learn what faults to avoid as likely to give you away.” [Aids to Scouting, p. 136.]