The Galilean telescope is constructed around two lenses, a double-convex objective on the nose of the tube and a double-concave lens as the eyepiece. This arrangement produces an upright image. The telescope is limited, however, by a small field of view and relatively low magnification. Largely for this reason, the Galilean type configuration lasted to the twentieth century only as field binoculars and to the present day as theatre glasses. The Keplerian telescope of Johann Kepler is configured with two double-convex lenses. This results in an inverted image but the convex eyepiece provides a larger field of view and higher magnification, and an inverted image is not a distraction for astronomical or most maritime use . The Schyrle telescope, invented by Anton Schyrle around 1625, adds two additional double-convex lenses to the Keplerian style. This four-lens arrangement returns the image to an upright position. The telescope also had a reasonable field of view and higher magnification than other telescopes of its time and competed with the Keperian telescopes. In 1757 John Dolland, a prominent scientific instrument designer and manufacturer in London, combined a convex crown-glass lens with a concave flint (lead) glass lens to correct for chromatic aberration. From Dolland’s patent of the achromatic lens in 1758, telescopes began being manufactured with achromatic objectives and multiple plano-convex lenses in the eyepiece (typically 4 lenses). This new breed of instrument was called the achromatic telescope. By the early 1800s, Dolland was making 9.5-inch diameter refracting scopes, and by the late 1800s, large refracting telescopes with apertures of over 30 inches were being supplied to observatories around Europe and America. The Yerkes telescope on display at the Chicago Exhibition in 1893 was 40 inches in diameter, 50 feet long and mounted on a tower 30 feet high.