The pressure of the atmosphere was first discovered by Torricelli in 1643. The barometer is not really a weather glass, but an atmospheric pressure measurer. The column of mercury in the tube rising or falling as the pressure of the air on the mercury at the open end of the tube becomes heavy (as in fine weather), or light, as in wet or windy weather. - There is a border around the image. Image size is correct. Many sizes available.
