The statement in court of facts like these points not so much to the cunning of the man Graves, but to the way in which, from the time of his taking up residence in Edinburgh as "a medical student," he must have been shadowed and kept under observation. The deciphering of the code, the certainty as to paper and envelopes used, and other things that came out at the trial, are small points in themselves; but they go to show that, if the German secret service were relatively as good to-day as in the days when Stieber used his intelligence to keep the system ahead of all others, Graves would never have come to a British jail; for, in the first place, the German secret service would not have employed a man who already knew too much, and, in the second place, as soon as any methods were known to the British police they would have been changed for others, even to the code which could be interpreted without the aid of a key. With regard to the quality of treachery, latent in all spies, the German secret service does its best to overcome this difficulty by the retention of a certain portion of the pay with which the spies are credited. When once a man or woman has fairly entered on the work of espionage a proportion of the pay is held back by the paymaster, so that there is always a considerable sum owing. This is supposed to act as an incentive to loyalty, and in most cases it undoubtedly has that effect, for no man likes to commit an act which will involve the forfeiture of a sum of money really due to him. Bearing in mind the cupidity of the average spy, it will be seen that no stronger deterrent of treachery could be devised.