Category Archives: History

Astronomical Clocks – Literally and Metaphorically

Posted on by

Astronomical Clocks – Literally and Metaphorically

The term astronomical clock is one that is used fairly loosely. Effectively any clock that shows astronomical information – as well as the time – can be so classified. They can show the location of the sun in the sky, for example. In addition to that they can show the position of the moon – and further information such as its phase and its age. Others go further and show the current sign of the zodiac or even go as far as showing a rotating map of the stars.

Going and Going and Going …

Posted on by

I bought some batteries, but they weren’t included. So I had to buy them again.

Steven Wright

Cocktail Party Physics: batteries not included

Some historians believe primitive batteries were used in Iraq and Egypt as early as 200 B.C. for electroplating and precious metal gilding. Around the 1790s, through numerous observations and experiments, Luigi Galvani, an Italian professor of anatomy, caused muscular contraction in a frog by touching its nerves with electrostatically charged metal. Later, he was able to cause muscular contraction by touching the nerve with different metals without a source of electrostatic charge. He concluded that animal tissue contained an innate vital force, which he termed “animal electricity.”

Caveat Emptor

Posted on by

I remember walking to lunch one day back in 2002, in early October, discussing some shootings that had been reported either that morning or the morning before. This was not a normal topic for conversation — shootings in the DC area are not uncommon — but these were sniper attacks and not taking place in the “bad” sections of town. After news of a few more attacks rolled in, there was a palpable sense of uneasiness that began to permeate the area, rising to out-and-out fear. People, including myself, changed their behavior about going out in public areas; I remember putting off getting gas until I could go to a station where I would be on the inboard side of the pumps and not present myself as a target to someone who might be hiding across the street. A few days later, an FBI employee was shot at a Home Depot parking lot a block or so away from that station — a store in a mall I frequent, and within walking distance of my abode (this has been empirically determined, repeatedly). I’ve stood in that lot, and often drive by the lot across the street where the snipers’ car must have parked.

It doesn’t much matter that the odds of getting shot were small. Fear is a raw emotion. When pitted against rational thought, it’s a good bet that fear is going to win, even if the level of fear is not rational. John Allen Muhammad and Lee Boyd Malvo terrorized the people of the greater DC area for three weeks and killed ten people. Today, Muhammed is scheduled to die, and barring an intervention by the governor, he will. I’m not generally a supporter of the death penalty; I think it’s handed out too freely and I have a hard time reconciling it with the notion of a civilized society. But today, Muhammed is scheduled to die, and I find that I have no problem with that.

In That Case, It's All Good

Posted on by

Notorious ‘man-eating’ lions of Tsavo likely ate about 35 people — not 135, scientists say

Sounds like they should have gotten off with a warning. For the first fifty, file it under “cats will be cats.”

I love the wording here:

Two world renowned man-eating Tsavo lions are seen stuffed and on display at Chicago’s Field Museum of Natural History Monday

Stuffed? Not even room for a wafer-thin mint?

Columbus Sailed the Ocean Blue …

Posted on by

The map that changed the world

The Waldseemuller map was – and still is – an astonishing sight to behold. Drawn 15 years after Columbus first sailed across the Atlantic, and measuring a remarkable 8ft wide by 4½ft high, it introduced Europeans to a fundamentally new understanding of the make-up of the earth.

The map represented a remarkable number of historical firsts. In addition to giving America its name, it was also the first map to portray the New World as a separate continent – even though Columbus, Vespucci, and other early explorers would all insist until their dying day that they had reached the far-eastern limits of Asia.

The map was the first to suggest the existence of what explorer Ferdinand Magellan would later call the Pacific Ocean, a mysterious decision, in that Europeans, according to the standard history of New World discovery, aren’t supposed to have learned about the Pacific until several years later.

Beauty is in the Vision-Response of the Beholder

Posted on by

Skulls in the Stars: Lord Rayleigh on Darwin

Darwin set out to show that insects play a crucial role in cross-pollinating plants, carrying pollen from one flower to another, and he published his results on orchids in a book in 1862, Fertilisation of Orchids. Among those results is the insightful observation that the colors and scents of flowers had evolved to attract insects and optimize the cross-pollination process.

This observation is what Rayleigh seems to be commenting on, and mildly criticizing. Rayleigh suggests that Darwin’s argument leads to the conclusion that insects must have vision similar to human vision — otherwise, why would a flower which is pretty to us be pretty to an insect? Rayleigh argues that this is a rather large assumption to make based on the limited evidence available in that era.

It’s well-known now that many insects are sensitive to UV, and plants look quite different to us in that spectrum. I have no idea what they look like to the bugs.

Renaissance Wrestling

Posted on by

Via the Giant’s Shoulders #16, I found Arcsecond: The Renaissance Man Uniform Gravitational Acceleration SMACKDOWN

The post is interestig enough, but what really got me was the following pictoral representation of perfect squares:

267image3

If you keep adding up the odd numbers, you get the next perfect square (i.e. sum the quantity (2i-1, from 1 to k, and you get k^2). You see this by adding a new “L” of dots to the previous square, which always has 2 more dots that the previous one, i.e. it’s the next odd number in the sequence, and it makes a new square.

That is so cool! If I had previously known this, I had forgotten it. And I can easily imagine this being taught to me ages ago, and not making quite the same impression because I couldn’t fully appreciate the elegance of it.

Dear Sir: Trick or Treat

Posted on by

Letters of Note: The Masked Letter

Written by a frustrated Lt. General Sir Henry Clinton during the Revolutionary War in 1777, this beautifully crafted Masked Letter is a perfect example of early coded correspondence. The letter reads perfectly well on its own, however only when you place a mask over the paper does the true meaning appear. Incredibly clever, and surprisingly successful as both the letter and mask were sent to the recipient (in this case John Burgoyne) along different routes.