to satisfy himself that the staff of his embassy understand not only the use of the cipher itself, but the extreme importance of guarding it from unauthorised eyes. And certainly the ambassador ought not to adopt the indolent practice, of which I have known one or two cases, where the less important part of a despatch was written en clair, and the ambassador himself added the vital part in cipher. Action of that kind is a masterpiece of futility, for it leads directly to the compromise of the cipher itself. For if the letter fall into enemy hands it will not be difficult for a clever spy to divine the manner of the sentence in cipher from the context written en clair.
In a word, the ambassador and his staff should guard a cipher as they would the inmost secrets of their own hearts. A really effective cipher is literally worth far more than its weight in gold.
General Duties.It is the duty of ministers residing at foreign courts to take steps to see that nothing is there published contrary to the honour or reputation of their sovereign, and to take all measures necessary to prevent the circulation of stories and rumours prejudicial to his interests. The ambassador must take care to protect the interests of all his master;s subjects, both in such matters as the free exercise of their religion, in which he should even offer his embassy as an asylum for those who are persecuted,