lunes, 10 de enero de 2011

Inventions and discoveries


The dawn of discovery

A long slow sequence of invention and discovery has made possible the familiar details of our everyday lives. Mankind's programme of improvements has been erratic and unpredictable. But good ideas are rarely forgotten. They are borrowed and copied and spread more widely, in an accelerating process which makes the luxuries of one age the necessities of the next.

The story is a disjointed one, since inventions and discoveries occur in a random fashion. They are described here in an approximately chronological sequence.

Two million years of stone technology represent the first long era of discovery at the start of human history. The use of fire, more than 500,000 years ago, is also a discovery. And some Stone Age artefacts (such as winged arrow-heads to stick in the flesh of the prey, or hooks carved in bone) have almost the quality of inventions. But these are developments of such an extended nature that they seem different in kind from the discoveries and inventions of more recent history.

Perhaps the first two ideas worthy of the name of 'invention', even though invented many times in many different places, are the eye of a needle and the string of a bow.

Needle and thread: from 15,000 years ago

In districts where warm clothing is necessary, Stone Age people stitch skins together with threads of tendon or leather thongs. For each stitch they bore a hole and then hook the thread through it.

The development of a bone or ivory needle, with an eye, speeds up the process immeasurably. The hole is now created by the same implement which then pulls the thread through, in an almost continuous movement. Needles of this kind have been found in caves in Europe from the late palaeolithic period, about 15,000 years ago. Several are so thin as to imply the use of materials such as horsehair for the thread.

The bow and arrow: from 15,000 years ago

The sudden release of stored energy, when a forcibly bent strip of wood is allowed to snap back into its natural shape, is more rapid and therefore more powerful than any impulse of which human muscles are capable - yet human muscles, at a slower rate, have the strength to bend the strip of wood.

The principle of the bow is discovered about 15,000 years ago. Bows and arrows feature from that time, no doubt both in hunting and warfare, in the regions of north Africa and southern Europe. The wood is usually ewe or elm. Stone Age technology is capable of producing sharp flint points for the arrows, often with barbs to secure them in the victim's flesh.

Making fire: more than 10,000 years ago

At some unknown time, before the beginning of settled life in the Neolithic Revolution, humans learn how to make fire. No doubt the discovery happens at many different times in many different places over a very long period. The knowledge of how to create a spark, and to nurture it until it develops into a flame, is an intrinsic skill of human society.

Almost without exception Stone Age tribes, surviving into modern times, have evolved in isolation their own methods of making fire. It is likely that the same was true when all humanity lived in the Stone Age.

The most common way of making fire is by friction, using a fire drill. This consists of a stick of hard wood, pointed at one end, and a slab of softer wood with a hole in it. If the point is placed in the cavity and rapidly twirled (by rubbing between the palms, or by means of a bow string looped round and pulled back and forth), the softer wood begins to smoulder. Shreds of dry tinder, placed in the smouldering cavity, can be carefully blown into a flame.

Another more sophisticated technique involves flint and pyrite. Evidence of both methods is found in neolithic tombs.


Read more at: www.historyworld.net

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