light through a prism, diffracting the sunlight into a rainbow of colors
splashing onto a distant wall. In a stroke of genius, Newton arranged a
second prism in the path of the isolated colors, curious to see if another
dispersion of a second rainbow occurred. Dear Reader, what is your guess
—does another rainbow ensue, or is it maintained as that selfsame color?
Or another?
The answer: the same color emerges from the second prism. With this
result, and others, Newton concluded that sunlight, or white light, is
composed of the colors of the rainbow. The experiment to confirm this is
to angle a series of prisms, or mirrors, into one focal point. Colors flow in,
and white light emerges. “Newton’s experiment of sunlight refracted by
two prisms—so ingeniously conceived, carefully performed, and
exquisitely narrated—came to be seen as a landmark in the history of
science. It established a great truth of nature. It created a template for the
art of reasoning from observation to theory. It shines as a beacon from the
past so brightly as to cast the rest of the Society’s contemporaneous
activity to relative shadow.”^26
During the “miracle years” in Woolsthorpe, Newton also performed the
foundational work on gravitational theory; exploring how the moon was
held in balance above the world, spinning and rotating, without flying
away or crashing down to earth. Using only his basic estimations and new
mathematics, Newton was able to prove to himself that all objects have
gravitational pull, and for the first time in world history, was able to grasp
why objects fell, why water flowed, why cannon balls arced in the air as
they were shot from a cannon, and why the celestial bodies traveled across
the sky. These concepts would underpin his laws of thermodynamics in
years to come, but for now, wandering around the manor, Newton could
take pleasure in gazing up at the moon and understanding what forces held
it in balance.
For that matter, Newton was allowed a full measure of satisfaction
everywhere he looked. The moon, orbiting overhead, sunlight reflecting
off rivulets in the Woolsthorpe pastureland, apples plopping onto the
orchard sod, the arced trajectory of a stone thrown by a neighbor boy, and
even the function of his own eyes all were, to him, the function of the
mechanical laws he was discovering. A deeply religious man, Newton’s
insights convinced him that everything around him conformed to his
conception of a “clockwork universe,” an orderly reality that he could