| Nobody knows who invented spectacles | | Roman tragedian Seneca (4 BC–AD 65) is said to have read "all the books in Rome" by peering through a glass globe of water. A thousand years later, presbyopic monks used segments of glass spheres that could be laid against reading material to magnify the letters, basically a magnifying glass, called a "reading stone." They based their invention on the theories of the Arabic mathematician Alhazen (roughly 1000 AD). Yet, Greek philosopher Aristophanes (c. 448 BC-380 BC) knew that glass could be used as a magnifying glass. Nevertheless it was not until roughly 150 AD that Ptolemy discovered the basic rules of light diffraction and wrote extensively on the subject. (The laws of diffraction was formulated much later by Snellius, between 1600 and 1620.)venetian glass blowers, who had learned how to produce glass for reading stones, later constructed lenses that could be held in a frame in front of the eye instead of directly on the reading material. It was intended for use by one eye; the idea to frame two ground glasses using wood or horn, making them into a single unit was born in the 13th century.In 1268 Roger Bacon made the first known... | |
| | Before Two Portraits of My Mother | | I love the beautiful young girl of this portrait, my mother, painted years ago when her forehead was white, and there was no shadow in the dazzling Venetian glass of her gaze. But this other likeness shows the deep trenches across her forehead's white marble. The rose poem of her youth that her marriage sang is far behind. Here is my sadness: I compare these portraits, one of a joy-radiant brow, the other care- heavy: sunrise—and the thick coming on of night. And yet how strange my ways appear, for when I look at these faded lips my heart smiles, but at the smiling girl my tears start. | |
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