Screws

Posted on 2013-01-08 by arjaybe

Robertson Screws
I believe I’m coming out of my solsticial somnolence now, so it must be time to make a post. It might as well be about something useful.

Some of the first things humans made were likely shelters. Originally they were just fitted together as best as could be. The boughs and fronds, first used for shelter right where they grew, later collected and used elsewhere, had their ways of fitting together. At some point other materials started to be used. Sticks, stones, lengths of vine or root, used as braces, shims and connectors. Then it was possible to construct a shelter that was more than a lean-to, though its form was still largely dictated by the materials used.

When we began to imagine what the dwelling should look like before building it, then we needed to be able to fasten the pieces together in arbitrary ways. And we needed to get systematic about it, instead of always having to improvise. Notches in sticks and logs would help them lock together. They would continue to be tied and notched for ages, then pegs would join the toolkit. It’s known that woodworkers in ancient Egypt used pegs to fasten wood together. It meant drilling a hole with a bow drill, like an archer’s bow with its string wrapped around the drill bit. Pulling it from side to side caused the string to turn the bit.

The Romans improved on that with the auger. They also invented forged iron nails, or at least took credit for it. Until the late seventeen hundreds, all nails were made by hand – forged, beaten or cut to shape. That’s also about the time the metal screw became commonplace, when machines were being developed that could mass produce them. Handmade metal screws first appeared in Europe three hundred years earlier, and wooden ones were used by the ancient Greeks.

robertsonTo turn in a screw takes a screwdriver. Modern screws have specially designed heads to fit a specific type of tool. The most common are the slot, the x-shaped Phillips, the hexagonal Allen and the square Robertson. The best of the bunch is the Robertson. The screw and driver were invented in 1908 by Canadian P.L. Robertson. He got a patent in 1909, but that didn’t help when an English licensee stole his rights. It cost him a lot of trouble and money to get them back and he would never license their production again, even to Henry Ford.

Now Robertson screws are rare in the UK and barely at 10% of the screw market in the US. But in Canada they account for 85% of screws sold.

rjb

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Solstice

Posted on 2012-12-21 by arjaybe

Newgrange, Ireland – Credit TJP Finn – CC-BY-SA

Thud, son of Thog, stood on The Rock watching for the Sun to go down. Behind him burned the fire, which he had kept going for the last week. It was working just as his father said it would. Although the Sun set further south each day, its retreat was slowing down. It was being drawn back by fire, a spirit of its own kind. Tonight, if Thud was worthy of the trust passed on to him by Thog and held by the tribe, the Sun would reach its lowest point in the southern sky, pause, and begin its long journey back.

Thud gave The Rock a sharp rap with the butt of his staff, as Thog had done before him. The purpose was to ensure that the Sun paid attention and remembered to come back. It couldn’t be allowed to fall asleep and drop over the edge or it might never return. Besides, it was cold and he needed to be doing something. His job wasn’t over until the Sun rose in the morning. He needed to be certain that the ritual worked.

No one knows for sure how long people have been performing rituals at the winter solstice, but we know for sure that many have and many still do. Maybe not as far back as Thud and his father Thog, but certainly at least 5,000 years.

In Ireland there is a stone structure called Newgrange which has been dated to more than 5,000 years before present. This megalith – literally, big stone thing – is built in a circle, like its famous English cousin, Stonehenge. Both of them are built so as to mark the position of the Sun precisely at winter solstice. Newgrange is a few centuries older than Stonehenge, but they served much the same purpose: to provide a place where people could monitor and probably celebrate the passing of the solstice.

Update: Newgrange is also a burial site. The body there presumably belonged to a person of privilege, nobility of some kind. As was apparently not uncommon amongst those people, it is also the product of an incestuous union, either brother and sister or parent and child. Read about it in this Science News article.

There’s another one in Scotland called Maeshowe. There are hundreds of megaliths all over Europe. All of them mark the solstices or the equinoxes or both. Similar structures exist in the Middle East, Asia, Africa and the Americas. The ancestors of the Pueblo people in New Mexico, the Chacoans, built an array of structures across kilometers of land. Not only did the individual parts have seasonal and astronomical features, the whole extended design did, too.

So far, all the archeological evidence for seasonal and astronomical rites is in the neolithic era. Neolithic refers to the latest part of the stone age. It’s when people began farming, domesticated animals for work and to eat and made great advances in pottery and textiles. The growth of settlements and a small population explosion lent themselves to the development of elaborate societies. They also provided the labor necessary to build large stone structures that weren’t strictly required for daily life.

That wasn’t possible in Thud’s time. It was all he could do to get enough wood to keep the fire going. And nobody was going to drag big stones around for him, as much as they might respect him and the memory of Thog. So we don’t have any megalithic evidence of his labors. Hunter-gatherers don’t leave as much of a mark on the ground as farmers do. But the return of the Sun is equally important to Thud and his tribe as it will be to their descendants living in towns. So he raps The Rock again and hunkers down in his furs, ready to stand vigil on the longest night of the year.

rjb

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Taste

Posted on 2012-12-16 by arjaybe
Photo credit - Kimli

Photo credit – Kimli

The sense of taste is much simpler than the sense of smell. Whereas we can distinguish thousands of different smells, there are only four (or six, as will be seen later) basic tastes. The four are sweet, sour, salty and bitter, each identified by a class of taste buds on the tongue and the roof of the mouth.

Sweetness is detected primarily near the tip of the tongue. Those taste buds can detect the shape of the hydroxyl groups found in sugar molecules. Sour receptors along the sides of the tongue respond to the acids in sour substances. Salt receptors, also along the edges, detect the metal ions, such as sodium, in salts. Complex nitrogen-containing compounds called alkaloids are detected as bitterness at the back of the tongue.

Sweetness tells us if the fruit or vegetable is ripe. Sourness might put us off unripe fruit or food that is going bad. Saltiness alerts us to the presence of chemicals that are essential to the proper functioning of our cells. Alkaloids are often poisonous. Their bitter taste is our warning. Basic survival depends on the four basic tastes.

There’s more to taste than that, though. There is the vast array of flavors we can identify when we combine tastes with smells. And there is actually a fifth category of taste called “umami.” Umami is the sensation stimulated by the presence of glutamate. Glutamate is the most common amino acid, accounting for almost half of the protein in plants and almost one fifth of animal protein. Proteins are made from amino acids. Although we can’t taste proteins themselves, we can taste their constituent amino acids as they start to break down in our mouths. Being able to detect the presence of such essential food elements is a pretty obvious benefit.

With the five basic tastes, alone or together, combined with thousands of smells into a huge catalog of flavors, we humans can have a very rich relationship with food. Throw in texture, or “mouth feel,” like smooth or creamy and so on, along with the recent discovery that we can taste fat, and a person could spend their whole life just trying new food sensations.

At this time of year it’s good to have good taste. We have turkey, shortbread, oranges, chocolate and so on in an endless stream of intoxicating seductions. Chewing a shortbread cookie sets off a burst of activity. The sugar activates the front of the tongue, where sweetness receptors abound. Salt stimulates the sides. Protein arouses umami. Vapors rise up the back of the nose where they engage the sense of smell. Along with the evolving chemical combinations in the mouth and nose, there exists the mechanical world of mouth feel. The crumbling and dissolving. The smoothness of fat. It all combines to make you want to swallow so you can take another bite.

The sense of taste is simply profound.

rjb

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