XV
THE SCOVELL CIPHERS
By the very great kindness of Mr. G. Scovell of Brighton, I have had placed at my disposition the papers of his great-uncle, General Sir George Scovell, G.C.B., who served during the Peninsular War in the Intelligence branch of the Quartermaster-General’s department. In the beginning of 1812 the number of intercepted French dispatches in cipher which came into Wellington’s hands, through the happy activity of Julian Sanchez and other guerrillero chiefs, began to be so considerable that the Commander-in-Chief thought it worth while to detail a member of his staff to deal with them. Captain Scovell was selected because of his ingenuity in this line, and became responsible for attempting to interpret all the captured documents. They were made over to him, and, having done what he could with them, he placed the fair-copy of the ‘decoded’ result in Wellington’s hands, but seems to have been allowed to keep the originals—which were, of course, unintelligible because of their form, and therefore useless to his chief. The file of documents which thus remained with him is most interesting: they range in size from formal dispatches of considerable bulk—eight or ten folio pages long—down to scraps of the smallest size written on thin paper, and folded up so as to go into some secret place of concealment on the bearer’s person. Some of them look as if they had been sewed up in a button, or rolled under the leather of a whip handle, or pushed along the seam of a garment. I take it that these must all have been entrusted to emissaries sent in disguise, Afrancesados or peasants hired by a great bribe. Presumably each of these scraps cost the life of the bearer when it was discovered—for the guerrillero chiefs did not deal mildly with Spaniards caught carrying French secret orders. The large folio dispatches, on the other hand, must no doubt have been carried by French aides-de-camp or couriers, whose escorts were dispersed or captured by the partidas at some corner of the mountain roads between Madrid and the head-quarters of the Armies of Portugal and Andalusia.
The cipher letters are of two sorts—in the first (and more numerous) class only the names of persons and places, and the most important sentences are in cipher—invariably a numerical cipher of arbitrary figures. In the other class the whole dispatch is written in figures, not merely its more weighty clauses. The reason for adopting the former method was that it saved much time; the transliterating of unimportant parts of the dispatch (such as compliments, and personal remarks of no strategical import) would have taken many extra hours, when it was necessary to get a letter sent off in a hurry. But, as we shall see later on, there was grave danger in using this system, because the context might sometimes allow the decipherer to make a good guess at the disguised words, after reading that part of the letter which was not so guarded.
Occasionally a French dispatch is ciphered after the same infantile system that readers of romances will remember in Poe’s Gold Bug or Conan Doyle’s Sherlock Holmes, where letters or numbers are merely substituted for each other—where, for example, 2 always means letter e, or 25 letter r. This sort of cipher is dangerously easy to an expert reader, especially if the words are separated from each other, so that the number of letters in each can be counted. Take, for example, a letter sent to Soult in 1813 by Cassan, the blockaded governor of Pampeluna[797]. Only one precaution had been taken in this cipher-epistle, viz. that elaborate care has been taken to defeat the attempt of the reader to arrive at results by counting what figures appear most frequently, and so deducing by their repetition that these must be e (the most frequently used letter in French, as in English), s, i, a, t, and other common letters. This is done by having six alternative numbers for e, four each for a and i, three for t, s, and n. Taking the simple phrase
47.50.40.41.14.26
58.24
3.51.10.36.44.23.17.24.10.50.53.27
47.46
11.18.39.17.46.21,
which deciphers into ‘depuis le commencement du blocus,’ we see that e appears five times, but is represented by both 50, 24, and 44; u three times, but varied as 14 and 46; m thrice, varied as 10 and 36. This made the reader’s work harder, but not nearly so difficult as that required for certain other ciphers: for the whole set of signs, being not much over 60 in number, there was a limited amount of possibilities for each figure-interpretation. And the words being separated by spaces, there was a certainty that some of the two-letter units must represent et, de, ce, eu, du, and similar common French two-letter words. As a matter of fact this particular dispatch was deciphered in a few hours owing to the lucky guess that its initial words
10.45.23.21.16.2.41.25
5.24
10.4.25.24.3.9.8.5
might be ‘Monsieur le Maréchal,’ the preliminary address to the intended recipient. This hypothesis was verified at once by finding that this rendering made good sense for the two-letter words 23.24 = ne, and 10.2 = me, lower down in the letter. After this all was plain sailing.
But the usual French cipher, the ‘Great Paris Cipher’ as Scovell called it, was a very much more complicated and difficult affair, as the list of figures, instead of being only a few score, ran to many hundreds. And of these only some few represented individual letters, more were parts of a syllabary: ma, me, mi, mo, mu, for example, had each a figure representing them, and so had ab- ac- ad- af- ag- &c. Moreover, there was a multitude of arbitrary numbers, representing under a single figure words that must often be used in a dispatch, such as hommes, armée, général, marche, ennemi, corps d’armée, canons. In addition there was a code of proper names, e.g. 1216 meant the River Douro, 93 Portugal, 1279 Talavera, 585 King Joseph, 1391 General Dorsenne, 1327 the Army of the South, 1280 Soult, 1300 Wellington, 400 Ciudad Rodrigo, &c. If the King wished the Duke of Dalmatia to send 9,000 men of the Army of the South to Talavera, he had only to write
‘585 désire que 1280 dirige 1156 (neuf) 692 (mille) 1102 (hommes) de 1327 sur 1279.’
He would then cut up désire and dirige into the syllables de-si-re and di-ri-ge, for each of which the syllabary had set figures; there were also arbitrary numbers for sur, de, and que. So the whole sentence would take up only fourteen numbers when written out.
It would seem at first sight that to interpret such a dispatch would be a perfectly hopeless task, to any one who had not the key to the cipher before him. That the admirably patient and ingenious Scovell at last made out for himself a key from the laborious comparison of documents, was nevertheless the fact. He was started on the track by the fortunate circumstance that most of the intercepted dispatches were only partly in cipher. Marmont would write
‘Avec les moyens que j’ai, et 798, 1118, 602, 131, 1112.663.1135.502 au delà de Sabugal,’
or
‘J’avais donné l’ordre que 1003, 497, 1115, 1383, 69,711, 772, 530, de descendre cette rivière et de se mettre en communication avec moi.’
Clearly the cipher-figures in the first case have something to do with a march on Sabugal, in the second with orders to some general or body of troops (to be identified hereafter) to march down a river which the context shows must be the Tagus. This is not much help, and the task looked still very hopeless. But when intercepted dispatches accumulated in quantities, and the same cipher-figures kept occurring among sentences of which part was written out in full, it became evident that various cryptic figures must mean places and persons who could be guessed at, with practical certainty. Occasionally a French writer completely ‘gives himself away’ by carelessness: e.g. Dorsenne wrote on April 16 to Jourdan,
‘Vous voulez de renseignement sur la situation militaire et administrative de 1238:’
obviously the probable interpretation of this number is ‘the Army of the North,’ and this is rendered almost certain by passages lower down the same letter. Equally incautious is King Joseph when he writes to Marmont,
‘J’ai donné l’ordre au général Treillard de 117.8.7 la vallée du 1383, afin de marcher à 498.’
Considering the situation of the moment 117.8.7 must almost certainly mean evacuate, 1383 Tagus, and 498 some large town.[798] [The particular dispatch in which this occurs is on a most curious piece of paper, half an inch broad, a foot long, and excessively thin. It is bent into twelve folds, and would fit into any small receptacle of one inch by half an inch. I fear the bearer who had it on his person must have come to a bad end.] Suchet also made Scovell the present of some useful words when he wrote on September 17 to Soult,
‘Le Général Maitland commande l’expédition anglaise venue de 747: O’Donnell peut réunir 786 692 1102 en y comprenant le corps de l’Anglais Roche. Le 19 août je n’avais que 135 692 1102 à lui opposer.’
Here it is quite clear that ‘747’ means Sicily; that ‘692.1102’ in the two statements of forces means thousand men. A little guessing and comparison with other cryptic statements of forces would soon show that 135 meant 7 and 786 meant 12.
Notwithstanding much useful help it was still a marvellous feat of Scovell to work out by the end of 1812 no less than nine hundred separate cipher-numbers, ranging in complexity from the simple vowel a to the symbol that represented ‘train des équipages militaires’! He must have had a most ingenious brain, and unlimited patience. Down to the end there remained numbers of unsolved riddles, figures that represented persons or places so unfrequently mentioned that there was no way of discovering, by comparison between several documents, what the number was likely to mean.
Sometimes very small fish came into the net of the guerrilleros, and were sent on to Wellington; take, for example, the tiny scrap containing the pathetic letter of the young wife of General Merlin, of the cavalry of the Army of the Centre—I fear that the bearer must have fallen into the hands of Julian Sanchez or one of his lieutenants, and have had short shrift:—
‘Mon cher Ami,—Depuis ton départ je n’ai reçu qu’un seul mot de toi—pendant qu’il arrive des courriers (c’est-à-dire des paysans) du quartier général. Mon oncle qui écrit régulièrement dit toujours qu’on se porte bien, mais tu peux te mettre à ma place! Je crains que ta goutte ne soit revenue, je crains tant de choses, qui peut-être passent le sens commun, mais qui me tourmentent. Je ne dors plus, et n’ai d’autre plaisir que celui de regarder ma fille, qui se porte bien. Encore si elle pouvait m’entendre et me consoler! Adieu! Je suis d’une tristesse insupportable, parce que je t’aime plus que moi-même.—Mercédes.’
It may suffice to show the general character of a typical cipher-dispatch if we give a few lines of one, with the interpretation added below—the following comes from a dispatch of Marmont written on April 22, 1812, to Berthier, from Fuente Guinaldo:—
Le roi après m’avoir donné l’ordre
1060 462 810 195 1034 1282
de faire par- tir deux divisions
971 216 13 192 614 20 90 92
et plus de la moi- ti- é de la
1265 582 637 851 809 388 177
cavalerie dis- po- ni- ble, et avoir
669 112 923 2 786 692 1102
ré- du- it à douze mille hommes
le nombre de troupes que j’ai disponible m’ordonne
13 1040 1003 370 860 400 817 69 862 718 1100
de chercher à pren-dre Ciudad Rodrigo lors que je ne ai
423 815 591 710 850
pas un canon de siège!
It will be noted that of all the words only partir, moitié, disponible, réduit, prendre, required to be spelled out in the syllabary: single fixed numbers existing for all the common words, and for the military terms siège, cavalerie, and division.
It was, of course, only by degrees that Scovell succeeded in making out the bulk of the French phrases. In Wellington’s dispatches there is often, during the spring and summer of 1812, an allusion to information only partly comprehensible, obtained from captured letters. On June 18 (Dispatches, ix. p. 241) Wellington writes to Lord Liverpool that he ‘is not able entirely to decipher’ the intercepted papers that have been passing between King Joseph and Soult and Marmont. On June 25th he sends to the same recipient the happy intelligence that he has now the key to King Joseph’s cipher. Yet again, on July 16th (Dispatches, ix. p. 290)—with No. 36 of the file catalogued below before him—he says: ‘I have this day got a letter from the King to Marmont of the 9th inst. in cipher, which I cannot entirely decipher: it appears, however, that he thinks Drouet will not cross the Tagus, and I suspect he orders General Treillard to collect some troops in the valley of the Tagus, and to move on Plasencia.’ The interpretation was correct, save that Treillard was to move not on Plasencia but on Aranjuez. The code-numbers for the two places were neither of them known as yet. But by September all essential words were discovered, and Wellington could comprehend nearly everything, unless Joseph or Soult was writing of obscure places or distant generals.
A list of the whole of Scovell’s file of 52 French dispatches may be useful: those whose number is marked with a star are wholly or partly in cipher, the remaining minority are in plain French without disguise. It is clear that Wellington had many more French papers not in cipher, which did not get into Scovell’s portfolio.
| Date. | Sender. | Recipient. | Contents. | ||
|---|---|---|---|---|---|
| 1. | Mar. 6, | 1812 | Col. Jardet | Marmont | Long interview with Berthier. He says you must ‘contain’ Wellington in the North. All else in Spain matters comparatively little. |
| 2*. | April 11 | ” | Marmont | Brennier | See that Silveira does not molest my communications. |
| 3*. | April 14 | ” | Soult | Berthier | Marmont has betrayed me, and caused the loss of Badajoz. Synopsis of Andalusian affairs. |
| 4*. | April 16 | ” | Marmont | Berthier | As I prophesied, my raid into Portugal produces no effect: we begin to starve. |
| 5*. | April 16 | ” | Dorsenne | Jourdan | I refuse to acknowledge the king as controlling my army. |
| 6*. | April 17 | ” | Soult | Berthier | Details of the fall of Badajoz, ‘événement funeste.’ |
| 7*. | April 22 | ” | Marmont | Berthier | I have been starved out of Portugal. Have seen no British troops, save a few cavalry. |
| 8*. | April 23 | ” | Foy | Jourdan | Send me food. My division is nearly starved. |
| 9*. | April 25 | ” | King Joseph | Dorsenne | I am your Commander-in-Chief. Send me a report of your army. |
| 10. | April 26 | ” | Gen. Lafon- Blaniac[799] | Gen. Treillard[800] | News from Andalusia at last: Soult has failed to save Badajoz. |
| 11*. | April 28 | ” | Marmont | Dorsenne | Send me 8,000 quintals of wheat at once. |
| 12*. | April 28 | ” | Marmont | Berthier | I have sent Bonnet, as ordered, to invade the Asturias. |
| 13. | April 28 | ” | Gen. Lamar- tinière[801] | Clarke | I send parole of Colquhoun Grant, a suspicious character. The police should look to him[802]. |
| 14*. | April 29 | ” | Marmont | Jourdan | If I keep troops on the Tagus, I am too weak on the Douro and Tormes. I must draw my divisions northward. |
| 15*. | April 29 | ” | Marmont | Berthier | I find that five British divisions were chasing me last week. Wellington is very strong in the North. |
| 16*. | April 30 | ” | Marmont | Berthier | Send me a siege-train, I am helpless without one: also plenty of money. |
| 17. | April 30 | ” | Marmont | Gen. Tirlet[803] | Come up at once to join my army. |
| 18*. | May 1 | ” | Jourdan | Marmont | We will keep unhorsed guns for you at Talavera, so when moving South bring gunners and horses only. |
| 19*. | May 1 | ” | King Joseph | Dorsenne | You are placed under my command. Obey my orders. |
| 20*. | May 1 | ” | Jourdan | Dorsenne | Send a division to Valladolid, to support Marmont. |
| 21*. | May 1 | ” | Jourdan | Marmont | You must send more troops to the Tagus: Drouet is hard pressed in Estremadura. |
| 22*. | May 1 | ” | Jourdan | Berthier | Wellington is advancing in Estremadura. Marmont must send troops southward. |
| 23*. | May 1 | ” | King Joseph | Berthier | Observations on the military situation. |
| 24*. | May 1 | ” | Col. Bousseroque | Gen. Doguerau[804] | Technical artillery matters. |
| 25. | May 20 | ” | Proclamation by Suchet | The King is appointed Commander-in-Chief in Spain. | |
| 26*. | May 26 | ” | King Joseph | Soult | Hill has stormed Almaraz. Why was not Drouet near enough to save it? |
| 27*. | May 26 | ” | Jourdan | Soult | Hill has stormed Almaraz. Try to re-open communications with Foy. |
| 28*. | June 1 | ” | Marmont | Jourdan | The fall of Almaraz means that Wellington will attack me next. He is not threatening Soult, but me. |
| 29*. | June 22 | ” | Marmont | King Joseph | I stop in front of Salamanca manœuvring. I dare not attack Wellington till Caffarelli’s reinforcements arrive. |
| 30*. | June 24 | ” | Marmont | Caffarelli | I am manœuvring opposite Wellington. Your reinforcements are required at once. |
| 31*. | July 1 | ” | Marmont | King Joseph | When the Salamanca forts fell, I retreated to the Douro. I cannot fight Wellington till I get 1,500 more horse and 7,000 more infantry. |
| 32. | July 1 | ” | Suchet | King Joseph | Narrative of guerrilla war in Aragon. |
| 33. | July 1 | ” | Suchet | King Joseph | Favour shall be shown to Afrancesados. |
| 34*. | July 6 | ” | Marmont | Jourdan | I had to retreat to the Douro because Caffarelli sent no help. Can you lend me Treillard’s cavalry division? |
| 35*. | July 7 | ” | King Joseph | Soult | Send 10,000 men to Toledo at once. |
| 36*. | July 7 | ” | King Joseph | Marmont | I shall march to your aid in a few days, when my troops are collected. |
| 37*. | July 22 | ” | Suchet | King Joseph | I am much worried by Maitland’s approach. Have beaten Joseph O’Donnell at Castalla. |
| 38. | July 29 | ” | Gen. Lafon- Blaniac[805] | King Joseph | Madrid remains tranquil. |
| 41*. | July 30 | ” | Marmont | King Joseph | We can never hope to unite. My army retires via Lerma on Burgos. |
| 42. | Aug. 2 | ” | Gen. Espert[806] | King Joseph | Wellington is marching on Segovia. |
| 43*. | Aug. 7 | ” | King Joseph | Marmont | Communicate with me by the Somosierra Pass. |
| 44*. | Aug. 12 | ” | Suchet | King Joseph | I am much alarmed at the possible results of Maitland’s landing. |
| 45*. | Aug. 12 | ” | Soult | Clarke | The King is betraying the Emperor and negotiating with the Cadiz Cortes[807]. |
| 46*. | Sept. 17 | ” | Suchet | Soult | Explains situation in Valencia. |
| 47*. | Dec. 9 | ” | King Joseph | Napoleon | Plans for reorganizing the armies. |
| 48*. | Dec. 22 | ” | King Joseph | Napoleon | Plans for next year. Should I make Burgos my capital, and hold Madrid only as an outpost? |
| 49*. | Jan. 8, | 1813 | King Joseph | Napoleon | Soult is intolerable. Let D’Erlon replace him. Send us money. |
| 50*. | Jan. 28 | ” | King Joseph | Napoleon | Your decision about Soult shocks me. I shall send him away on my own authority. |
| 51*. | Mar. 14 | ” | King Joseph | Gen. Reille | D’Erlon shall look after Salamanca. Send two divisions to hunt the guerrilleros. |
| 52. | Mar. 16 | ” | Col. Lucotte | King Joseph | Discouraging news from Paris. No men or money for Spain! |
In addition to the ciphers, the Scovell papers consist of short diaries of Major Scovell for the Corunna Campaign, and for 1809-10-11-12-13, as also a large bundle of reports and maps of roads and passes in Portugal, all the papers concerning the raising of the Corps of Guides, a number of notes and reports on suggested travelling forges for the artillery and engineers, and some whole or mutilated contemporary Spanish newspapers. There is some curious and interesting information scattered through all of them.