JANUARY 21
THE FIRST DIFFERENTIAL

JANUARY 21
THE CRITICAL MASS

THE FIRST DIFFERENTIAL

The differential and the Antikythera mechanism are closely related. Even considering the technical knowledge in those times (Antikythera mechanism was found at the bottom of the Aegean sea in the early 20th century, but it is supposed to be an invention of the 1st century B.C., i.e., around 2000 years ago), it appears as the tip of the iceberg. It is said that this mechanism is the prototype that was left after very updated technology for those days, which, for unknown reasons, was aborted. Although the clockwork mechanisms used were already known by the Alexandrines (from Alexandria), the device has a particular and vital part, the differential, which would be reinvented many centuries later.

When and where the differential was invented is still subject to discussions. The French say that it was invented by a clockmaker named Pécqueur, in 1828; while the English say it was made by one of them, someone called Wiillis, in 1841 and improved by Starley later in 1877.

What is a differential? It is a mechanism that allows each of the driving wheels to rotate at different speeds mainly when turning corners. It is found in cars, railways and in helicopter rotors as well. Thanks to the differential, the drive shaft moves the half shafts through gears, which are oddly still called planetary and satellite gearing.

And what was the Antikythera instrument for? The hypothesis that says that the device was a planetarium has been gaining followers. It is said that the sunrise, the moon phases, the orbit of the five planets already known, equinoxes, several astronomic cycles, the months and days could be calculated. Recent research evidenced traces of the inscriptions Nemea” and “Olympia”, "which means that it was also used to fix the date for the Nemean Games and the Olympia Panhellenic.

What was that device like? It was made inside a shoe-box-sized shell and had a frontal and two lateral dials which were supposed to have hands that indicated different numbers. Inside, there was a clockwork mechanism made up of thirty gears with triangular teeth which were supposed to be triggered by one or two cranks.

THE CRITICAL MASS

One of the questions brought up by the Antikythera mechanism (a planetarium apparently built in the 1st century and found inside a Greco-Roman ship wreck that has sunk in the Aegean Sea) is how such an advanced technology could coexist with the poor technology Greeks and Romans had. Another question that comes up is why the Greek science, or its successor, the Romans, could not make the same leap the Industrial Revolution made in the 18th century, and why they got stuck and declined slowly but steadily.

The most common answer is that, immerse in a society where slavery was practiced, nobody would even think about using machines to save efforts. The second part of this speculation is that, apparently, there was a strong prejudice against technology among the ancient philosophers. This situation is studied by the historian Bertrand Gille: Within the Greek technical culture, those aspects make up a vicious cycle: when work is looked down on, slavery becomes necessary, and looking down on slaves makes work become worthless. This version expressed by Gille is the most systematic one.

It is true that the Greco-Roman culture was not the only one that got stuck at a certain level; it seems that the same happened with Mayans and Incas. Now then, why did English, in the 18th century start the Industrial Revolution? Because at a certain point several factors that produced a cause-and-effect chain came along; for example, mining resulted in the development of the steam engine, which led to advances in metallurgic and transport and required new mining developments; and from then on, to different fields. The Greek did not reach the critical mass, if they had, they could have undoubtedly changed the course of history.