Leonardo and Printing

Posted by Jerry on July 18th, 2004 — Posted in History, Technology, Travel, Writing

I have been reading Carlo Pedretti’s recent book on Leonardo da Vinci – it seems that Leonardo took a great interest in the emerging information technology explostion of his time – printing. And he designed a printing press with an automatic sheet feeder. But despite arranging and paginating some of his work to facilitate printing, none of his works were printed in his lifetime. In about 1505 Leonardo designed a basic system for the simaltaneous printing of text and images – a method eventually used by William Blake some two centuries later. It is fascinating work.

He also revisits the notion of an automobile, to be driven by springs which was also designed by Leonardo – And now the Italians are working on a full scale working model. It is as yet incomplete, but the site is well worth visiting!

Cheers
Jerry

The Lost Army of King Cambyses

Posted by Jerry on July 7th, 2004 — Posted in History, Journal, Travel

Herodotus writes of the disappearance of some 10,000 members of the Persian Army in the Western Sahara around 2,500 years ago. According to Herodotus a fierce sandstorm engulfed the army and they disappeared without trace.

I was drawn to this story by a TV program on the ABC last night called “The Lost Army of King Cambyses” It would seem that three years ago an Egyptian archaeologist named Aly Barakat found ancient arrowheads and a dagger in an isolated spot near Siwa. The arrow heads and dagger were consistent with ancient Persian design – yielding the tantalising possibility that the remains of the lost army might be nearby.

The story remained tantalising, however, but there were plausible explanations as to why it is reasonably likely that the remains of straggler groups from the army might yet be uncovered. The arrowheads, and some human remains were found near the oasis town of Siwa, which appears to be the site to which hey were heading when they ran out of luck – and food – and water.

Other campaigns of King Cambyses suggest that logistics was not his strong point – as his aborted attack on Ethiopia proved. So it is reasonable that, in an effort to travel light and fast, the Persians carried insufficient supplies – sacrificing logistics for mobility, perhaps hoping to find provisions along the way. (source: http://nefertiti.iwebland.com/herodotus/cambyses.htm).

The Western Sahara is forbidding country, and with food running short it is likely that the troops first ate the pack animals and then perhaps started on each other – driven progressively mad by thirst and hunger. Fatigued and confused and with little sense of where they were heading, it is likely they began to split into smaller groups, and then were overwhelmed with a ferocious sand storm.

Groups may have huddled close to the base of the great butte formations in a last effort to find shelter, and there became buried. However they died, it was almost certainly not as a massed army – not with a bang but a whimper.

But the finding of a dagger and some arrow heads lends weight to the view that Herodotus was not so unreliable an historian as some would suppose. He almost certainly relied on dubious sources such as travelers which may or may not have been corroborated by independent multiple sources, but it now appears that – in the case of the disappearance of Cambyses’ army – the source had some credibility.

A fascinating, if tragic story.
Download Herodotus’ history of Egypt from project Gutenberg here

Cheers
Jerry

Gargoyles – old and new

Posted by Jerry on June 17th, 2004 — Posted in History, Journal, Travel, Writing

Ever since I spent a bit of time poking around the UK I have been fascinated by the phenomenon of gargoyles – part rook plumbing devices, part caricature, and part irreverent iconography. The site above discusses the history of these strange carvings, and this one is of a modern maker of gargoyles I was intrigued also at the discovery that Star Wars’ Darth Vader appears as a gargoyle gracing the roof line of the cathedral in Washington DC in the USA!

Cheers
Jerry

Viking Optics – sun stones and lenses

Posted by Jerry on June 13th, 2004 — Posted in History, Technology

I recently read an old copy of New scientist from 7 November 1998 which carried a story about viking lenses. It says that the vikings made high quality quartz lenses – aspheric ones which have an elliptical, rather than spherical, shape. These were made on simple lathes and were apparently used for as fire starters or to cauterise wounds. There are examples of such lenses in museums in Munich and Sweden and no doubt elsewhere. There is a web page discussing viking lenses and research into them by Olaf Schmidt of the University of Applied Science in Aalen, Germany.


Rock Crystal Lenses from the Viking Harbor Town of Fröjel, Gotland in Sweden

I was talking to a Dane recently about this, and he told me that the vikings also used things called sun stones for navigation, and he suggested that they somehow lit up when held aloft, even on cloudy days, to enable them to locate the sun and thereby derive a position. I suggested that it might not have been far fetched if, say, some sort of crystalline stone which might act like a polarising lens. This might be able to filter diffuse light and reveal the direction of a non-polarised light source, which would have been the sun. And after a bit of a search online found that my hypothesis might be correct! Indeed Norway is one source of a naturally occurring felspar which had polarising properties – the other major source was Iceland where the vikings had continuous settlements.

Certainly the Vikings were excellent navigators and they had ships well capable of traversing open ocean, rather than just being brown water vessels, so it is quite likely that among their many navigational tools, they might have used a polarising filter.

Cheers
Jerry

Leonardo’s helicopter – model much improved

Posted by Jerry on June 7th, 2004 — Posted in History, Journal, Technology

Another quick update on my model of Leonardo’s helicopter – I have made a larger diameter rotor and achieved a couple of flights across the room. The rotor diameter is now about 18cms (about 7.5 inches) and made from cereal box card. The helix winds one and a half times around (one circle plus a half, with the lower circle split along the radius to the centre and the extra half attached with masking tape. There was some sag, which I rectified with a masking tape brace – you will notice that Leonardo’s helicopter design had string braces to support the rotor structure – I guess he had problems with sag too 😉 Anyhow here is a picture of my model (current configuration as flown). The drive is the same spinning-top launcher that I was using before.

Leonardo\'s helicopter - version 2

And Leonardo’s one for comparison:

Image as displayed on the Leonardo Museum in Vinci – they also have a model based on Leonardo’s helicopter, but using fabric rotors the way Leonard’s original envisaged.

Cheers
Jerry