“When the light of the sun is spread out by a prism into a spectrum, the bands of color are striped also by some narrow, dark lines, which we now understand to mark the specific wavelengths at which light is absorbed by various elements in the sun—iron, magnesium, calcium, and others. Isaac Newton experimented with prisms and lenses in the years 1668–72, and based an entire theory of the nature of color and of light on the solar spectrum. He did not report the absorption lines. Was his equipment too primitive to reveal them? In 1961, William Bisson at M.I.T. built an apparatus like Newton’s, reconstructed the original experiments, and showed that the absorption lines would have been plainly visible. Bisson and a colleage reported this in a note in Science in 1962, concluding, ‘‘We saw the lines,’ and wonder why Sir Isaac Newton failed to achieve the distinction of being the founder of the science of spectroanalysis.’ The question provoked Edwin Boring to argue, later that year, that Newton?s theory, not his apparatus, had no place for the lines; Newton’s theoretical expectations blinded him to the evidence. Boring added, ‘To the observing scientist, hypothesis is both friend and enemy.’”

—Horace Freeland Judson, from The Search for Solutions, 1980.