# 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

of squared paper beneath are regarded as corresponding to the 5 TP impulses and
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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