## The Newmanry History## Part of the General Report on Tunny (1945)## Page 314 |
Tony Sale's Codes and Ciphers |

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- 43B Page 314

each impulse is marked off with an upright ink line according to the chi length of

that impulse. All subsequent work is done in pencil. A letter or Delta-K is

arbitrarily chosen and assumed to have Delta-PSI'=/. On the Tunny machine of the

time the psis came in at the second letter and moved on automatically from the

second to the third place. So the third place of Delta-K was the first possible

TM dot. At the assumed Delta-PSI'/ position we enter the Delta-X letter in

impulses (= Delta-K since Delta-PSI'= /), and the 5 Delta-X signs thus derived

are entered on their respective chi-periods throughout the Delta-K. These signs

are underlined to distinguish them from other Delta-X signs deduced from them.

Now from every Delta-X sign thus entered we can use the property Delta-K(i,j) -->

Delta-X(i,j) to deduce one Delta-X sign on each of the other four impulses. For if

the underlined Delta-X character is on impulse i and gives Delta-X(i) = Delta-

K(i), then in accordance with the above property we deduce Delta-X(j) = Delta-

K(j) , for j = each of the other 4 impulses, thus obtaining 4 fresh Delta-X

characters which each have probability b provided that the position originally

selected is in fact a TM dot. Similarly if we find Delta-X(i) not = Delta-K(i) we

assume Delta-X on the other four impulses to be the opposite of Delta-K. These

deduced Delta-X signs are written into 5 'cages' of width 41,31,29,26 and 23

respectively. Thus all signs deduced for Delta-X3, from underlined Delta-X signs

on impulses 1,2,4 and 5 are written out on a width of 29. An example of a

Delta-X3 cage is given below:

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