VISIBLE AND INVISIBLE

A straight and long street is visible from my window. It is lined on both sides by houses. And there is a park in the middle. But what is at the end of the street is not visible to me - the distance seems to be covered with misty haze. I put on my glasses - and the foggy haze disappears. I see the trembling leaves on the bushes, red and silver-gray roofs of houses, strewn with yellow sand paths in the park.

 Nearsighted Person Vision
Nearsighted Person Vision

 And behind them, high, high, at the very sky - dark lilac outlines of the mountains. And even higher is a star. It flickers a little and seems lonely in the pale evening sky.

But as soon as you remove the glasses, everything disappears at once: the star, and the outlines of the mountains, and the roofs of houses ... A wonderful power is laid in the small pieces of glass inserted into the frame of the glasses! They bring the farthest closer, make it visible. Such pieces of glass are called lenses.

I am a short-sighted person and I need glass lenses through which you can look into the distance. They are thicker at the edges than in the middle and are called concave or scattering. And there are still convex or collecting lenses. These are most often needed by older people. In the distance, they see well, but do not distinguish closely located objects.

 Collecting and Divergent Lenses
Collecting and Divergent Lenses
Probably, people with poor eyesight had a bad time in those distant times when they still did not know glasses. Someone with age gradually lost the ability to do the usual work, while still quite physically strong. And how it was for educated people? Neither can you compose yours or read other people's "opuses." Right, a tragedy and only: they had to use servants and slaves as scribes and readers...

Fortunately, this did not happen often: there were far fewer educated people in those days than today. And there were few shortsighted people, then the people did not sit in front of the screens day and night!

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