A visual history of calculation devices, from the human hand to mobile apps.

1. MACHINES MANAGE NUMBERS
A VISUAL HISTORY OF CALCULATORS

2. The very first counting device
was likely the human hand…
Simple, reliable, and extremely
versatile, it’s affordable and
needs no batteries or special
training for basic uses.
However its ubiquity (it enjoys
near-100% market penetration)
means that earning a living with
your hands requires some effort
to develop useful skills!
http://en.wikipedia.org/wiki/Finger-counting
HUMAN HAND

3. These ancient tally sticks
unearthed in the Swiss Alps (top)
are on display in a museum
today.
Their use continued into the
medieval era, as shown in the
lower photo which records a
debt of 20d each on 32 sheep,
which was owed as a tithe in
Hampshire England.
The basic idea of using marks
inscribed on bone or wood to
count likely arose over 40,000
years ago.
http://en.wikipedia.org/wiki/Tally_stick
TALLY STICKS
"Medieval tally sticks" by Winchester City Council

4. Counting boards of many
kinds were invented in
multiple societies throughout
antiquity.
Considered a direct precursor
to the abacus, they could be
as simple as lines scratched in
dirt, or beautiful artisanal
creations of wood, marble
and even precious metals.
http://en.wikipedia.org/wiki/Counting_board
COUNTING BOARDS

5. The term “Abacus” wasn’t
coined until the 14th century, but
is now used to describe a variety
of inventions - some dating back
thousands of years.
At one time or another, cultures
on every continent developed
systems involving rows of objects
– pebbles, beads, even knots in
twine – coupled with ingenious
and often surprisingly efficient
methods for performing useful
calculations with them.
http://en.wikipedia.org/wiki/Abacus
http://www.hps.cam.ac.uk/people/robson/words
-pictures.pdf
ABACUS

6. Slide rules are perhaps the best
known pre-electronic calculation
device, still used in some parts of
the world today.
In fact, astronauts on the Apollo
missions carried slide rules (lower
photo) as backups to their primitive
onboard computers for making
calculations related to course
corrections and fuel consumption.
With hundreds of varieties adapted
to various fields of mathematics,
skilled users can compete on
speed and accuracy with
electronic calculators in many
areas.
http://en.wikipedia.org/wiki/Slide_rule#History
http://airandspace.si.edu/collections/artifact.cfm?objec
t=nasm_A19840160000
SLIDE RULES
Smithsonian Air and Space Museum

7. Early mechanical calculators
emerged in the 17th century and
grew steadily in complexity and
usefulness, until being displaced
by electronics in the latter half of
the 20th century.
The tremendous variety and rich
heritage of this field could easily
become its own separate series,
but one interesting 20th-century
example is on the next page…
http://en.wikipedia.org/wiki/Mechanical_calculator
http://en.wikipedia.org/wiki/Comptometer
http://en.wikipedia.org/wiki/Pascal%27s_calculator
THE RISE OF
THE MACHINES

8. The legendary Curta (1948-1972) still
has fans and users today. Famed for
its flexibility and durability, working
collectables can sell for thousands of
dollars on eBay.
Its innovative, ingenious (and heavily
patented) design enabled it to do
more with far fewer moving parts
than any precursor.
Remarkably, its design was
completed while the creator was
imprisoned in a Nazi concentration
camp!
http://en.wikipedia.org/wiki/Curta
CURTA

9. The first electronic calculators
appeared in the 1960s (photo,
left), although some purely
electrical models – relay-based,
and the size of an office desk –
were available as early as 1957.
Calculators remained rare and
expensive novelties until the mid-
1970s, when the TI-30 (pictured,
right) debuted at the equivalent
of about US$100 in today’s
money.
http://en.wikipedia.org/wiki/Calculator#History
ELECTRONICS

10. Today, the standalone
calculator has largely
been supplanted by
software applications
running on desktops,
laptops and mobile
devices.
Yet most retain the same
basic user interface
pioneered over 100 years
ago by the early
mechanical adding
machines.
TODAY

11. Other fascinating and noteworthy stories are part of the history of
mechanical calculation – in particular, I recommend reading about
the Difference Engine, Galileo’s Military Compass and the
Antikytheria mechanism for those interested – but in the spirit of
focusing on stories relevant to the history of accounting, they have
been omitted.
You may also enjoy browsing some vintage NCR (National Cash
Register) ads from the 1950s and 60s here! In the spirit of fair
warning, many of these do little to promote gender equality in the
workplace…
MORE TO THE STORY