Download my history of the calculating instruments in pdf (English)


The modern world was designed with slide rule and mechanical calculator conceived in the 17th century

Still the youth ignore these slide rule that anticipated our technology. I think it's useless to teach math without teaching how calculations were made in the past.

With my free e-book "Was There Life Before Computer?" the teachers can easily illustrate the old computing systems.

To preserve the memory of the slide rule, the pascaline and the mechanical calculator, I organize national and international exhibitions and conferences, where the ancient instruments could be tested by the public.

The project is now suspended due to other commitments. To better understand the old technology I had also added exhibits on the history of communications and pre-GPS navigation. All programs still available in Italian and English. The exhibits were presented in London, Berlin, San Francisco, Poznań, Slubice, Trento etc., as well as every year from 2007 until 2018 at The Cagliari Festival Scienza.

Download the short history of engineering before computers by Nicola Marras

Short history of engineering before computers (English)

Download Was There Life Before Computer by Nicola Marras

The mechanical calculator, the slide rule, astro navigation, crittography

Download the paper calculators by Nicola Marras

Aeronautical E6B, slide rule, nomograms, abaques

Download the presentation of the communication exhibit by Nicola Marras

Presentation of the exhibition on communications (Italian)

Download the presentation of the pre-GPS navigation exhibit by Nicola Marras

Presentation of the exhibition on pre-GPS navigation (Italian)

The modern computer has been built on these ancient instruments, conceived in the 17th century, that seemed irreplaceable. Galileo's compass was still useful on board aircraft carriers, the mechanical calculator and the pascaline were the driving force of the financial globalization. The slide rule, invented in 1622, served to design everything: from the James Cook's flagship to the Jumbo Jet!

Slide rule, 1663

Everard slide rule, 1663

Pickett 600 ES slide rule on the Apollo 11

The slide rule with Buzz Aldrin on the Apollo 11

It was Leibniz's dream come true:

"It is unworthy of excellent men to lose hours like
slaves in the labor of calculation which could be
relegated to anyone else if machines were used"

No invention ever made such a rapid impact. The automobile took more than twenty to establish itself. Electronics instead instantly defeated the competition. An unprecedented revolution.

Pascaline, a mechanical calculator from 1940

Pascaline, 1940: patented in 1645 and produced for 300 years

However, the transition was not painless because the ancient computers were used in every field. People had little faith in the new "electronic slide rule" and the factories inserted the old instrument on the back, for the sake of safety.

Sharp EL-429 electronic calculator, 1980

Sharp solar powered calculator with abacus, 1980

By now, however, the new technologies required computing power: shortly after Sharp presented the first mini computer, almost pocket-sized. The PC era was beginning.

Sharp PC 1500 electronic computer,1982

Sharp PC 1500 programmable computer with printer, 1982

A little investigation revealed to me that, for many students, the result of 2 + 3 x 4 is 20, not 14! With the slide rule, however, the pupils immediately recognize the order of the operations. The ascaline helps the little ones to easily understand addition and carry-over.

Was there life before computer? educational project has
represented Italy at the Science on Stage Europe Festival 2013

Old Calculators & Democracy

Today people punch numbers into a calculator and expect the calculator to provide the correct answer, the Art of Numeracy is no longer practiced and the world before computers almost forgotten. Now students learn mathematics while being illiterate about the history of mathematics, which is a false start. With a calculator, modified to give incorrect results, I show how easy one can make and no notice errors.

fake calculator

The operation that appears on the display is correct?
Can you detect if there is an error on the fly?

The electronic aids should not blindly be trusted. We need to understand and criticize what we do. Software could be buggy and the computer results have to be critically reviewed. In the past, with the old calculating devices, the operators were always aware of their actions and used to check the results.

Today instead many people think "I don't need to check, the computer knows better than me". Sadly, the thinking that "if an expert states it, then it must be true" is the basis of the Authority Principle, which leads to mental slavery.

@ Andy Singer

We'll believe anythings (if it lets us be lazy ...) @ Andy Singer

Teaching the traditional calculating instruments as a school of democracy may seem an overstatement, but nobody can be a free citizen if unaware of what he does or willing to discuss it. Not by chance democracy was born in the same country in which maths and geometry were born,. Uncritical use of the computer can lead people to press buttons mindlessly.

Scientific thinking and independence of ideas are not a natural product of intelligence, they must be cultivated steadily. A simple lesson about traditional calculation may help. A rational mind produces better decisions, better citizens and a better world.

Download Old Computing & New Generations by Nicola Marras

Old Computing & New Generations

"Old Calculators & Democracy" educational project has
represented Italy at the Science on Stage Europe Festival 2015

Exhibit of old calculators

Nicola Marras teachs pascaline and arithmometers

Even the little ones take an active interest:
pascalines and slide rule are not yet forgotten

Nicola Marras' Staff

Best staff best show!

The slide rule today

Analog calculators are disappearing from the market, the reliability and battery life of the new electronic models leaves no room. But in extreme conditions they are still used: they resist almost any temperature and are virtually indestructible as well as requiring no energy. An aeronautical E6B you can leave it in the freezer for a month, then boil it, throw it out of the window and then leave it in the sea at a depth of 100 meters: you recover it, drive over it with a car and it will always be perfectly functional! Furthermore, it is still difficult to build electronic equipment well protected against radiation. Their time is running out, however: read this article.

Dangerous Sliding

Download Dangerous Sliding

About this site

As obvious, I carry out my project in Italy and and this translation is much smaller than the original. However, here you will find a summary of my book on the history of the calculating instruments and all my educational material.

My works are provided under the terms of the Creative Commons License "BY-NC-SA 3.0".

The contents were largely produced by myself but there is also material owned by third parties and another was taken in the network, apparently of public domain. In general I applied for authorization to use, which unfortunately is not always possible. In any case is always shown on the author's name and a link to his personal website: if the name of the owner is not present must be considered the author as unknown to me.

If someone noticed that, unbeknownst to me, there is in this work copyrighted material is encouraged to communicate it to me, so I can properly cite the intellectual property or remove it. It is my intention to apply all the rules in force on the legal protection of intellectual property.

Nicola Marras Bio - @ ISRM

Download my history of the calculating instruments in pdf


Alte Rechenhilfen  Prehistoria informatica  David's calculating sticks
Nathan Zeldes  Lovett's sliderules  Rechenschieber  Ulisse Quadri

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