Famous scientists can be spectacularly wrong. Isaac Newton developed a new, correct idea about color, but was wrong about its impact on telescopes or microscopes. Isaac Newton (1643-1727) carried out experiments that showed how white light consists of different colors combined together, and how a telescope or microscope lens spreads out these colors, creating an image tinged with red or blue fringes, a problem called chromatic aberration. He concluded that it is impossible to reduce chromatic aberration in telescopes except by increasing their length. That led others to build aerial telescopes more than 100 feet long! But Newton was wrong. The solution involved using two different kinds of glass, soda lime and flint glass, one for a convex lens, the other for a concave lens. An achromatic telescope was made in the 1730s, but a good achromatic microscope wasn’t available until 1830, when Joseph Jackson Lister published a paper on how to make that device. Be sure to see “Revealing the Invisible: The History of Glass and the Microscope” on view at the Rakow Research Library before it closes on March 19!