•• REF ID:A68877 •• 

424 l'f. George Ila.son Drive 

'Arl1ngton, V1rgio.1a 8 Pebn&rJ 1949 

Pl'oteasol' Georg• E, MoC:racken 

911 25th Street 

·Dea Moine• 121 Iov& 

De~r Oeorge1 

. Under separ•te cover I am •ending 7ou the copy of 

ISIS tol' 1our autograph. · 

I have gone thl'ough the article again and compared it v1th the original article vbich 7ou wrote some 79ara 

ago and bad dittoed. Tbe·art1cle aa 1\ appears in ISIS 

is a ver7 great illproveaent on the or1g1n&1, although I 

must say tbat I found. certain ot the too~otea 1n the 

latter rather inter•sting. In particular, I appreciated the tranalat1ona of the Latin v~ch~ ot oourae, 7ou 

could not include in the ISI~ vera1on. 

Your article rem1Dded me that I bad at one time concluded to •ke uae ot the ten "ategariogra.Pb7" to &ppl7 

to vbat ,,. nov call the t1el4 ot "open cede" and I Will 

set the !erainoloSJ Commi~tee·to do •om•tb.1ng on it. . . 

On page 218 right atter the thingamajig vbich separate• the to1> section troa the bottom, there appears a line 

beginning "At the bA&d ot his vork Eircbel' p111nta (2) the tollov1ng paragraph ••• ." Wb&t on earth 1• the •(2)" the~• tort Ia it a 111.ap~int? 

I did not f1nd 7our deecript1on ot the ood.9 a1at .. too cle&:r. It •••• to • alao tbat 7ou aighi ba•• called 

·attention to the tact that t~Cll • ~ecbnioal JH1int ot view · the "decode" section ot lt1l'oher's coda 1• reallJ tM •encode11 and vice veraa, becauae obv1ou•1J it 1• onl7 1n th• 

Latin liat where "encode• and "decode 11 entries are identical 

and., since the vork vaa intended tor pol7gr&phic P'JrJ>O•••• 

the o.rrans•ent ror Latin waa not too eigniticant. Another 

·thine 7ou llight ba•• mentioned 1• that a.t;teapta have been 

:made .1n ver"S recent tiae• to do What Kircher att•pted • 

. ,• . 

@'pproved for Release by NSA on 07-15-2014 pursuant to E.O. 1352a 
•• REF ID:A688~7-

~ 

- 2 -

~eae attapte are exnap11t1ed 1n the Maroon1. International 

Co4-1 p,at. out a tn 1eara ago bJ the Marconi 'lelegrapb Co., . and a the Intern& t1onal Code or s1gna1a 1 put out bf the 

International ~elecOJ8Nrl1cat1on Union. 

· I am. a bit atr&id that 7ou have given too au.ch.credit 

to old •n Vigenel"e on page 22,. I do.n1t th~ that vigene:r.te 

vaa "one or the pea.teat cr1J)tographere "tho ever 11ved nor 

vae 1-t he ''who tiret 1nt1'odueed the basic idea ot polJ&lpba- betie substitution." !he latter goes back even beyond Porta 1 

'Who ment,1ona 1 t J Alber\1 certainlJ ueed an4 talked about 

pol7&lpbabetic aubst1tut1on. 

x vonde~ vheth•r 7ou have ever seen Mendelssohn's 

article on V1genere. It ~ou he.ven•t1 I Y111 be glad to 

ae:nd 7ou a reprint v1tb my coapl11.D.en"t;s. . . . 

On page 224 in the example ot cipher text, in the right · band col\lllln1 the .tOUl'th 1 tea should be "2-'" and not "''". 

You untortunatelJ carried thia error ove~ fl'oa the original article. I av tbat t:ou bad. &l.re&d1' picked up one tJP«)graph- 1cal error on page 216. vhicb ia a rathe~ unfortunate one. 

I checked ever1 single enc1pherment example! 

I, too, 1'1ah there were aoae exp18.Jl&t1on or tbat ver7 pecul.1&~ and not p&.l'ticul.&1'17 am.uaing atorr attributed to 

Po1't&t vhich you· have •ntioned on page 226., I wonder 

whether a. JDol'e careful ee&roh tbx-ough lt1rc~l' 'a text Jld.sht 

not give some olu•'I .. 

r1na111~ vitb retere.nce to the •Sic equa,re_ 1t 1a a 

ugbty 1ood thing that the •810 .l!Jqu&Jt• 1• ba•ed upon the 

number 34• becauee bad 1t been "33" or "'5" there are lots 

ot people who Yould aa7 tbat 1t retera to Bacon., Por it you.• 

BUJA the n\llierical valuea ot the letters ot the naae you 

set either '' or ,5, depending upon vb.ether th• letter •3• 

1• in the nol'tll&l sequence or not. It 11 poea1ble tbi&t & 

searob through •h• Xi~cher book ~ill give aoae a1gn1t1oanae 

to th• ll*b•r "'4... I•a eure it bad •Olle. 

· I b&ve, aa 7ou •••~ gone over t-W. •~t1cle prett7 oaretull7 and aoae or 117 o~nta ve probabl7 ot a mnor •1Bn1t1oan.ce, ;t bav• al.Mady told 1ou tbat I tbil:lk 7ou 414 an 

&dail'&ble P1•o• ot vork and one Which ia vorthYbile.. I Yill · be ver7 glad to bAve 1our comenta 011 IQ' oomme11t.1. . . With eoit41t,l peet1ng, I aa# S~cerel7 1oura,