A case of espionage which was tried in London revealed his methods,
one of his agents being arrested after having been watched for three
years.

Karl Ernst's trial confirmed the discoveries and showed up the doings
of men spies like Schroeder, Gressa, Klare, and others.

Also the case of Dr. Karl Graves may be still in the memory of many.
This German was arrested in Scotland for spying, and was condemned
to eighteen months' imprisonment, and was shortly afterwards released
without any reason being officially assigned. He has since written
a full account of what he did, and it is of interest to note how his
correspondence passed to and from the intelligence headquarters in
Germany in envelopes embellished with the name of Messrs. Burroughs
and Wellcome, the famous chemists. He posed as a doctor, and sent
his letters through an innkeeper at Brussels or a _modiste_ in Paris,
while letters to him came through an obscure tobacconist's shop in
London.

One of these letters miscarried through having the wrong initial
to his name. It was returned by the Post Office to Burroughs and
Wellcome, who on opening it found inside a German letter, enclosing
bank-notes in return for services rendered. This raised suspicion
against him. He was watched, and finally arrested.

He states that a feeling that he was being followed dawned upon him
one day, when he noticed in his lodgings that the clothes which he had
folded on a chair had been since refolded in a slightly different way
while he was out. With some suspicion, he asked his landlady whether
anyone had entered his room, and she, in evident confusion, denied