sequence of performance of ten electrically controlled operations which correspond 
to the recording of the ten figures O, 1, 2,..., 9. 
The storage register consists of a cylindrical assembly of ten conducting 
segments embedded in an insulating cylinder, and a number of wheels each carry- 
ing a contact fixed to a slip ring. The number of wheels should be equal to the 
largest number of figures which may be required. An electric brush on each wheel 
may be connected to any one of ten circuits after rotating the wheel until is contact 
engages the corresponding segment. Each circuit controls the setting of a figure. 
The electric current is applied to the brushes in turn; the figures can then be set 
on the machine in a succession pre-determined by the positions of the wheel con- 
tacts relative to the segments. In this way, a number set on a storing register 
outside the machine can be set on the setting register of the machine. In a similar 
way, the figures of a multiplier can be set in succession on the multiplier’s register 
of a ‘fully automatic’ calculator. 
It now remains to see how a figure appearing on a register of the machine, 
say the product register, can be transferred onto the setting register, or else trans- 
ferred to a storing register for late use. This can be simply done by mounting a 
suitably dimensioned storing register to engage the digit wheels of the machine 
register under consideration. A number which appears on the machine register 
will at the same time be recorded on the mounted register and can be automatically 
read off by means of the brushes. To have this number set on another storing 
register, it is necessary to have a setting mechanism which may be a simplified 
version of any of the setting mechanisms used in calculating machines. 
It appears therefore that the problems of storing a number and of commu- 
nicating numbers to the machine from the store and the other way round, can be 
simply solved by using the suggested form of storing register. 
Let us now consider the last requirement. The operations are usually con- 
trolled by various control keys which instruct the machine, to multiply, divide, 
add and so on. When provision is made to operate these keys automatically, the 
problem can be solved by setting the desired sequence on a storing register consist- 
ing of an appropriate number of segments and wheels. 
In the preceding paragraphs I have concentrated on suggesting improvements 
in the use of existing calculators. There is however great advantage in developing 
a new calculating machine which incorporates in it some registers of the type 
described above and which is suitably designed to make the best use of the idea. 
It should be emphasized in connection with the automatic performance of 
arithmetical operations that in photogrammetric calculations and many others, it 
is not usually necessary or advisable to perform the whole of a long sequence of 
operations automatically in one run. There are certain advantages in breaking up 
such a sequence into smaller sequences, to allow for inspection of the results 
after each sequence before proceeding to the next. Neither is it always neces- 
sary to have a sequence of operations conducted fully automatically to secure 
economy. It is quite sufficient for many purposes that there would be no need 
for the operation of the machine to intervene intelligently during the sequence 
of operations; and it would not be a serious shortcoming if the operator had to 
turn a handle or switch a key, for example as soon as he senses the end of an 
operation in order to start the next. This would reduce the cost and complexity 
of the equipment by cutting down the number of electric relays. The main point 
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