Drake-Nelson Code (1796)

The Code

A code of some 400 entries titled "CYPHER WITH CAPTAIN NELSON - F. DRAKE No.1" is presented by tonybaloney, of which a portion is given below after being sorted in numerical order.

It assigns code numbers to letters and words randomly (i.e., two-part code). Frequently used terms are given two or three numbers. Further, a single number may represent several variants. For example, 89 is listed as "th, is, ese, ose" and thus could be read either as "th", "this", "these", or "those." There are functional symbols such as "Take only first letter of the preceding number" (90, 126) or "Take only the first two letters of the preceding number" (140). Numbers above 400 are nulls. These features are also seen in French ciphers at the time as well as during the age of Louis XIV (see another article). (I do not have enough British materials to compare with this.)

The entries include "nelson, captain ...... 224", who was promoted to commodore under Admiral Jervis early in 1796, "bonaperte, general. 105.281", who won fame by crushing a royalist rebellion in Paris in October 1795 and was given command of the Army of Italy.

According to Hugo Mercier (2006), The Pursuit of Victory: The Life and Adventure of Horatio Nelson, Francis Drake (Wikipedia), a diplomat based in Genoa, gave Nelson two ciphers in March 1796, one for letters he writes to Nelson and the other for those from the latter.

Encoded Letter

A partially encoded letter from Drake to Commodore Nelson dated Venice, 16 July 1796 is presented by tonybaloney. According to Mercier (2006), Drake was an important person in the intelligence network established by William Wickham (Wikipedia).

The main portion of the above letter can be decoded as follows.

Col. Graham informs the admiral that the austrian army will commence their operations in a few days and it is by the express desire of Marshall Wurmser the austrian Commander in Chief, that the Colonel most earnestly requests the admiral to send with all possible dispatch some frigates into this sea (the adriatic) for the purpose of cove[r]ing the communication between trieste and the mouths of the po - as the magazine of the austrian must come by sea from trieste.
The Colonel further states that the whole plan of operations of the austrian army depends on this single point & that nothing can be done without it.

Thus, Drake asks Nelson to inform Admiral Jervis that the Austrian general Wurmser (Wikipedia), soon to commence operations, is requesting the British navy to cover his line of communication.

General Napoleon Bonaparte had taken over command of the French Army of Italy and had already won initial victories. He had taken Milan after the Battle of Lodi and in June laid siege on Mantua, the strongest Austrian base in Italy. The above letter is about a planned reinforcement of the Austrian army under Wurmser.

In the end, Wurmser was trapped in Mantua and surrendered the town in February 1797 (Wikipedia).

Dump for Verification

Col. Graham informs the admiral that the austrian army will commence their operations 381<in> 93<a> 85<few days> and it is by the express desire of Marshall Wurmser the austrian Commander in Chief, that the Colonel most earnestly requests the admiral to 192<s> 163<e> 189<n> 244<d> 19<with> all possible 276<dispatch> 192<s> 32<o> 75<m> 252<e> 314<frigate> 192<s> 381<in> 301<to> 89<th, is, ese, ose> 80<sea, men> ( 124<the> 93<a> 244<d> 195<r> 175<i> 120<a> 15<t> 362<i> 262<c> ) for the purpose of 262<c> 32<o> 247<very> 140<"Take only the first two letters of the preceding number"> 381<in> 177<g> 124<the> 284<communication> 249<b> 351<e> 15<t> 148<w> 252<e> 163<e> 189<n> 246<trieste> 151<and> 138<the> 75<m> 83<o> 119<u> 250<then> 140<"Take only the first two letters of the preceding number"> 192<s> 368<of> 260<the> 185<p> 32<o> - as the 44<magazine, s> 368<of> 124<the> 275<austria, n> 75<m> 119<u> 192<s> 15<t> 262<c> 83<o> 75<m> 351<e> By 80<sea, men> 339<from>
246<trieste> The Colonel further states that the whole 35<plan of operations> 368<of> 124<the> 292<austria, n> 346<army> depends on this single point & that nothing can be done without it

Decoding Table (Part)

1;dardanelles, the     51;port of bouc             101;bombard
2;blockade             52;geno, a, ese             102;troop
3;emperor, the         53;h                        103;"full stop"
4;certain              54;shore                    104;x
5;cape leucate         55;politics, of, the        105;bonaperte,general
6;division             56;lisbon                   106;enemy, the
8;twenty               57;f                        107;you
9;z                    58;fleet                    108;swed, e, n, ish
10;black sea           59;jervis, sir john         109;wallis, general
11;cartridge           60;sail, of                 110;ahrenberg, prince of
12;thousand            61;"full stop"              111;compleat
13;cape                62;ninety                   112;deck, ers
14;wallis, general     63;lavenza                  113;emissary, of
15;t                   64;indies, east             114;tuscany
16;bandol, town of     65;mediterranean            115;cape delle
17;toulon              66;pound sterling           116;expedition, to
18;embark, ation       67;hi, m, s                 117;cassi, town of
19;with                68;fort of brescon          118;tower of bouc
20;ciotat, town of     69;navy                     119;u
21;arsenal             70;secret intelligence      120;a
22;w, as, were         71;or                       121;corsica
23;battalion           72;monaco                   122;depart
24;brame, w            73;intercept                123;eleven
25;two                 74;gourjean, bay of         124;the
26;var, the            75;m                        125;we
27;possess, ion.       76;four                     126;"Take only first letter
28;martigues           77;k                        of the preceding number
29;king, the, of       78;impolitic                127;cadiz      
30;lead for a bullt    79;project, of              128;empire
31;regiment            80;sea, men                 129;captain
32;o                   81;frejus, gulf of          130;vado
33;naval stores        82;l                        131;twelve
34;insurrection        83;o                        132;went
35;plan of operations  84;half galley              133;antibes
36;ship, ping          85;few days                 134;conde, army of
37;reinforce, ment     86;merchant, ship           135;destin, e, ation, the
38;saint chamas        87;powder-magazine          136;eight
39;man                 88;rhone, mouths of         137;cannon
40;perpignan           89;th, is, ese, ose         138;the
41;galley              90;"Take only first letter  139;y
42;leghorn             of the preceding number"    140;"Take only the first two letters
43;pink                91;six                      of the preceding number"
44;magazine, s         92;viceroy of corsica       141;beaulieu, general
45;impracticable       93;a                        142;emigr, e, ant
46;laden with          94;cethe, town of           143;tunis
47;sicily              95;sixteen                  144;armament
48;rom, e, an          96;villafranca              145;spa, i, n, ish, iard
49;politic             97;well-disposed            146;crew, s of
50;mantia              98;tentative                147;boat
                       99;company                  148;w
                       100;dismantle               149;unservicable
                                                   150;to


©2015 S.Tomokiyo
First posted on 23 April 2015. Last modified on 29 April 2015.
Articles on Historical Cryptography
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