Within the next hundred years every major court and minor principality of Italy, Spain and France was using ciphers, and all the great systems of encipherment but one had been invented. Decipherment does not seem quite to have kept pace; indeed it was nearly four hundred years before the classic method of deciphering double substitutions was discovered. Now in cryptography as in other fields of human activity necessity is so much the mother of invention that it is difficult to believe that if the complex systems of cipher had been widely used, means of breaking them down would not have become as widely known as the ciphers themselves. As a matter of fact, practically all the ciphers of which samples have been preserved to us from periods before the Napoleonic era belong to relatively simple types. It is difficult to avoid the conclusion that the more elaborate systems, though they were developed early, remained buried for some time in the theoretical manuals of the men who invented them.
This theory is considerably strengthened by the fact that we know northern Europe, where the greatest development in deciphering processes subsequently took place, did not take readily to ciphers in the early days of resident ambassadors. There were two or three striking historical incidents which painted the unreliability of the existing systems of cipher across the continent (they will be described later); and the North had long since developed its own device for private communication. Under the pressure of the rising art of diplomacy this device began to develop into a regular system. Its basis was a code which is not a code—jargon, cant, euphuism, the erection into a regular method of expression of that system which had formed part of the means of communication used by the Venetian agents in the fourteenth century.
VI
Partly this method is inherent in the Teutonic languages themselves, which drop the precision of the Latin tongues for a tendency toward double meanings and involved images. One of the earliest written works in any northern language, the Prose Edda, is a handy manual of involved periphrastic metaphors for the use of poets.
“What shall we call the air?” says one passage. “The air may be called the ravens’ causeway; or the bearer of storms; or the woof of the winds.”
If figures of speech are constantly used, if they be sufficiently farfetched and involved, or if they have reference to something known only to a few persons, this sort of thing can be developed into a code which can be either written or spoken. It is difficult to state positive facts when dealing with so indefinite a subject, but it would seem that the inspiration for the use of this type of code for diplomatic purposes comes ultimately from the very root of the language growing through medieval thieves’ slang, which was already highly developed in the fourteenth century.
“These Babes of Grace,” says an early Elizabethan instruction for the training of young thieves, “should be taught by a master well verst in the cant language or slang patter, in which they should by all means excel.”
A good deal could be and has been written about these peculiar crooks’ codes, about which it is enough to remark here that they seem to have reached their greatest development in the early part of the nineteenth century. This was the period when a pair of initiates could carry on a whole conversation without an eavesdropper catching any more of it than the prepositions. Both Victor Hugo (Les Misérables) and Eugène Sue (Les Mystères de Paris) give some interesting examples, most of them already out of date when they were distilled into the books; and the famous Vidocq, who was on both sides of the law at different times, quotes a long song by means of which young members of the profession were taught its special language, not very good as a song but intended more as a school exercise:
J’ai fait par comblance
Gironde languepé,
Soiffant picton sans lance,
Pivois non maquillé,
Tirants, passe à la rousse,
Attaches de gratousse,
Cambriot galuché.*
The very facts that such a mnemonic rhyme should be necessary and that Vidocq, who was then a member of the police, could record it, marks the decline of thieves’ argot as a language or code, peculiar to the profession.
The fact is that the argot had obeyed the natural tendency all codes have, that of spreading to cover more and more of the possible exigencies of conversation, and in this process it had become so complicated and difficult as to fall of its own weight. The men for whom it was produced simply could not or would not spend the time and effort necessary to learn it. The early nineteenth century was also the period when police science enjoyed its great and rapid development, with most detective forces coming into being. It was instantly evident to such officers as M. Henry in France and Sir Richard Mayne in England that a man who could hang about criminals’ haunts as one of themselves could learn their argot, and through it learn anything else he wished to know about their operations. Smart detectives therefore made a business of learning argot, and the moment this happened it began to decline.
VII
A criminals’ code of sorts, common to the whole underworld, still exists, but it has become largely a matter of inflection and innuendo, with the inclusion of a few special identifying terms. The professional thief in E. H. Sutherland’s Professional Thief tells the following story:
“The language of the underworld is both an evidence of the isolation of the underworld and also a means of identification. A professional thief can tell in two minutes’ conversation with a stranger whether he is acquainted with the criminal underworld and in two minutes more what particular rackets he knows intimately. If a thief were in the can and another person were brought in, the first might ask, ‘Where were you nailed?’ The second might say, ‘In the shed.’ It is possible that an amateur might know that ‘nailed’ meant arrested but no amateur would use the word ‘shed’ for railroad station.
“I was eating supper in a cafeteria with an occasional thief who was a student in law school. Two coppers were sitting at another table near by. The occasional thief had selected our table and had not recognized them as coppers. They were not in uniform. My friend said loud enough so the coppers could hear, ‘Did you hear what Jerry Myers got?’ I knew alright Jerry got four years, but I was not going to let the coppers know we were talking about anyone who had received a bit, and I had to hush the youngster up. I could not say ‘Nix!’ as a thief might have said if the coppers had not been able to hear, for this in itself would have informed the coppers that we were worth watching. So I said, ‘I understand the doctor said he got tonsillitis.’ A professional thief would have sensed danger at once and would have carried on along that line, but my friend started in again, ‘No, I mean—’ but I kicked him under the table and butted in again with some more about tonsillitis. The police were watching us carefully and I could not office my partner by moving my eyes toward them. I had to get up and go to the counter for something more to eat. When I returned I picked up his book on Conveyances and looked at it and then asked, ‘Have you seen the new book on abnormal psychology by Dr. Oglesby?’ The policemen immediately got up and reached for their hats. I nudged my partner to look at them as they got up and you could see that each had a revolver in a holster. My partner now understood why I had interrupted him and he asked, ‘Why didn’t you tell me they were here?’ I had told him a half-dozen times in language any professional thief would have understood.”
VIII
It is impossible to say when and in what manner thieves’ slang got itself into a gold-laced coat and began to present diplomatic credentials. We sight only a few details through the fogs, just enough to be fairly sure that while ciphers were developing in Italy the diplomatic jargon-codes were coming into being at the opposite end of Europe. Margaret, the queen who united