Chapter 5
This quack remedy, promoted by Sir Kenelm Digby, was believed to heal wounds at a distance.
What is the powder of sympathy?
In 1714, merchants and seamen petitioned Parliament to take action on solving this persistent navigation problem.
What is the problem of longitude?
This English clockmaker, later nicknamed “Longitude”, was born in Yorkshire in 1693.
Who is John Harrison?
Harrison sought out this astronomer royal at the Greenwich Observatory as a gateway to the Board of Longitude.
Who is Edmond Halley?
Established by the Longitude Act, this body of scientists, naval officers, and officials judged proposals and awarded prizes.
What is the Board of Longitude?
The bizarre 1687 longitude scheme proposed sending this injured animal aboard ships to provide a time signal.
What is a dog?
This English monarch was reigning when the Longitude Act was passed on July 8, 1714.
Who is Queen Anne?
Before gaining fame as a clockmaker, Harrison spent much of his early life learning this skilled trade from his father.
What is carpentry?
This respected London watchmaker became Harrison’s patron after a single very long day of discussion.
Who is George Graham?
According to Newton, once this was lost at sea, it could not be recovered by any watch, no matter how good.
What is longitude?
Introduced by John Davis in the 1590s, this navigational instrument spared sailors from staring directly at the sun.
What is the backstaff?
This scientist, age seventy‑two in 1714, advised Parliament and dismissed the sea‑going watch as not yet feasible.
Who is Sir Isaac Newton?
Harrison’s first surviving clock, completed in 1713, was unusual because it was built almost entirely from this material.
What is wood?
Harrison’s first sea clock, completed after five years of work, is known by this designation.
What is H‑1?
Harrison ultimately realized he had to abandon this device, despite its great success on land, to build a timekeeper suitable for the rolling sea.
What is the pendulum?
This catastrophe, involving multiple shipwrecks near the Scilly Isles, intensified public pressure to solve the longitude problem.
What is Admiral Shovell’s shipwreck?
To win the top £20,000 prize, a method had to find longitude within this margin of accuracy.
What is half a degree of longitude?
This mathematical chart pasted inside one of Harrison’s early clocks reconciled solar (“true”) time with mean clock time.
What is the Equation of Time?
During the return voyage to England, H‑1 correctly identified this landmark, proving the ship was over sixty miles west of where the captain believed.
What is the Lizard?
By combining brass and steel strips, Harrison’s gridiron pendulum solved this long‑standing problem that plagued pendulum clocks.
What is temperature variation causing expansion and contraction?
These two mathematicians proposed anchoring signal ships at sea that used timed explosions of sound and light to determine longitude.
Who are William Whiston and Humphrey Ditton?
In 1714, Jeremy Thacker coined this term to describe his improved marine timekeeper.
What is a chronometer?
Two precision inventions—the gridiron pendulum and this friction‑free escapement—gave Harrison’s clocks unprecedented accuracy.
What is the grasshopper escapement?
Despite strong praise from the Royal Society, Harrison refused to send this later timekeeper to sea because it failed to meet his own standards.
What is H‑2?
This Flemish astronomer suggested in the 1500s that accurate clocks could help sailors figure out longitude at sea.
Who was Gemma Frisius?