Cambridge (pp 74–75)

In 1664, at the University of Cambridge, a young Daniel Waterhouse assists his roommate Isaac Newton in a meticulous project to map the movement of shadows against the passage of time.

“wheel by which the ship is steered” — Stephenson’s annotation: “Actually most ships of this day probably didn’t have wheels, because it was a relatively recent innovation; but as we’ll see in future volumes, Minerva is ahead of its time in some respects.

Modern day Pirates say it was in 1705 that the balanced ship’s wheel replaced the tiller — likely imported technology of the Indian or Chinese shipbuilders 1 — in use by the Dutch and Porteguese.”

“a gnomon angling up from the center” — A gnomon is the part of a sundial that casts the shadow; Newton’s dissatisfaction with the “naïve” Roman design reflects his burgeoning obsession with geometric precision and the irregularities of planetary motion.

“synchronization with King’s” — Stephenson’s annotation: “How did the Trinity’s bell-ringer decide when to ring? Why was this different from when the King’s bell was rung?” Any inconsistency in the bell-ringing would introduce “bumps” into Newton’s data, making the bell a flawed instrument for perceiving the sun’s movement.

“Heavenly radiance fills the æther” — In 17th-century physics, the Aether was a hypothesized invisible medium thought to permeate all space, serving as the necessary “fabric” through which light waves and gravitational forces were transmitted.

“the spectrum of colors concealed within the light” — This refers to Newton’s Optics, a series of experiments proving that white light is not a pure entity but a composite of all colors in the visible spectrum, which he demonstrated by refracting light through glass prisms.

Original annotations by: stephenson, seitz