is thrown to "normal", and the appropriate depth switched in on the rectangling
This is the usual Colossus rectangle method : it is often disadvantageous
for short texts because so much is lost by reduction to a multiple of 1271.
Note: Although the subtraction gadget can be used independently of the rectangle
gadget proper, it is too limited in scope to be of value.
the 3-way rectangling switch at the extreme right of the control panel has
two active positions : "Print scores" and "normal".
The other switches are on the rectangling panel. Any chi-wheel can be
multiply tested for making a rectangle : the corresponding switch of the bottom
of the rectangling panel must be thrown. This determines when carriage return is
operated and how many surplus scores are cancelled.
The subtraction gadget is controlled by a series of switches labelled 1 to
36, each number indicating the depth to be subtracted.
(g) The Cyclometers.
The Theta(ij)^2 significance test is based on the number of occurrences of
each possible value for the entries in a rectangle.
At the top of the rectangling panel is a row of cyclometers to record these
Below these is a row of jacks, one for each cyclometer. A pulse here steps
the corresponding cyclometer.
Below these again are two rows of jacks labelled 1,2,3.... A score of +-
Theta produces a pulse in the jack Theta.
These score jacks can be plugged arbitrarily to the cyclometer jacks.
(h) The punch.
Colossus 6 can make a rectangle in the form of punched tape. A negative
score is always represented by a cross in the fifth impulse, but otherwise a score
can be represented by an arbitrary letter, selected by plugging from a score jack
to a punch jack.
There is a score jack labelled CR which carries the pulse of the carriage
return at the end of each row of the rectangle. This is normally plugged to the
punch jack labelled 9oneback/ which punches / and adds a cross to the third
impulse of the preceding letter (c.f. Appendix 95).
(i) Rectangle not 99.
In any cell of the rectangle containing a place where Z = 9 adjacent to
another 9, this replaces the entry by zero. It is useful only for rectangles of