Humanity's use of the sun's energy extends far back into prehistory - By: fandydu

By this time tomorrow, and every day, there will be added to the earth about 120,000 extra people¡ª just about the population of the City of New York.
I am not talking about birthrates. This is net increase. To give you some idea of birthrate, look at the seconds¡¯ hand of your watch. Every second three babies are born somewhere in the world. Another baby! Another baby! Another baby! You cannot speak quickly enough to keep pace with the birthrate.

Of all the continents, the most drastic reduction in wildlife has occurred in North America, where the transition from a rural to a highly industrialized society has been most rapid. Among the victims are birds, mammals, and fish. We will never again see the passenger pigeon or the eastern elk. They have been wiped out. Of many other species, only a few representatives still survive in the wild.

Why should we care about the extinction of these birds and animals? The answer is simple enough. Every species that becomes extinct is gone forever. With each departure a small part of the diversity of nature that makes life so interesting is also gone. What has man got to look forward to¡ªendless cities and houses and roads that cross barren country devoid of birds and animals? Is that the world we want for ourselves and our children?

Looking through Glass,Nobody knows for sure who invented the first spectacles or who wore the first pair. Various old I European coins of the Middle Ages were stamped with eyeglasses, symbolizing the ability to see the truth.

The oldest lens known was found in the ruins of Nineveh. It was a lens of rock crystal with a diameter of 1 -y inches and a 4 ¡ª inch focus. Thus we know that the ancient Babylonians and Assyrians had discovered the magnifying power of certain transparent gems; but it was quite certain that spectacles were unknown to them and were equally unknown to the ancient Hebrews and Egyptians. There is no record of spectacles among the ancient Greeks either. The Roman Emperor, Nero, looked at various games and shows through emerald or ruby glasses which he held up to his eye. But this was not used as an aid to sight. He merely liked to look at things through the colored gem.

Spectacles seemed to have cropped up simultaneously in China and in Europe about the end of the thirteenth century. Macao Polo wrote (about 1260) that old people in China wear them" for reading fine print". A fourteenth-century record mentions that a certain Chinese gentleman gave a fine horse in exchange for a pair of spectacles.
These ancient Chinese spectacles were large oval lenses of rock crystal, rose quartz, topaz, and amethyst, set in tortoise-shell rims, fastened on the wearer with various devices. Some had brass bows which clamped against the temples; others were tied around the ears with a string, or fastened into hats. Often they had cords which passed over the ears and were kept in place by little ornamental weights which either hung down behind the ears or were drawn forward over the shoulders.

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Besides the direct conversion of sunlight into thomas sabo sterling silver electricity by means of photovoltaic cells, sunlight may be, I used to generate steam, which can then be used to power a turbine for producing electricity. One solar-thermal design, called a power tower, consists of a field of movable mirrors that surround a tower thomas sabo charms, at the top of which is a boiler.

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