HISTORY 135E

Department of History
University of California, Irvine
 Instructor:    Dr. Barbara J. Becker
 

Lecture 13.  Shrinking Time
 
Solving the Longitude Problem:  Artificial vs. Natural Clockworks


Clockmaker, John Harrison (1693-1776)  

1693 born in Yorkshire
1725 investigated effects of temperature change on expansion and contraction of metals

used results of experiments to design gridiron pendulum
1726 completed two "regulators" made of wood, accurate to within one second per month


 
1730

John Hadley (1682-1744) invented a new altitude-measuring instrument -- the "octant" or "Hadley's quadrant" -- that was accurate to within 3 mins of a degree (~ 3 mi)


Hadley's quadrant
1730 Harrison met with Astronomer Royal Edmund Halley and noted clockmaker George Graham despite fears Graham would steal his plans.  Instead, Harrison gained their support for his plan to build H1.
1735 H1 completed


H1:  weight = 75 lbs; size = 4 ft × 4 ft × 4 ft
1736 H1 sent on trial run to Lisbon
1737 Commissioners of the Board of Longitude meet for the first time
  • examine H1
  • advance Harrison £250 toward production costs of H2
  • promise additional £250 when H2 is completed

H2
weight = 86 lbs
size ~ H 4.5 ft × W 2 ft
(never tested at sea)

H3
weight = 60 lbs
size = H 2 ft × W 1 ft
(never tested at sea)
1739 H2 completed; bigger and heavier than H1; never tested at sea
1740 Harrison started work on H3; would take 17 years to complete and was not much smaller or lighter than H1 and H2; never tested at sea
1742 death of Edmund Halley; James Bradley (1693-1762) appointed third Astronomer Royal
1749 Harrison was awarded the Royal Society's prestigious Copley medal
1757 most of the work on H3 completed
1769 H4 completed; it was this smaller, lighter chronometer that won Harrison the Longitude Prize

H4
weight = 3 lbs
size = 5 in. diameter
 

1761

to

1762

 first voyage to test H4 made to Jamaica on the Deptford

by determining their position at sea using H4, the crew of the Deptford was able to correct the ship's course and avoid delays that would have resulted if they had relied solely on estimates based on traditional methods
1763 Nevil Maskelyne (1732-1811) published the first Mariner's Guide
1764 second voyage to test H4 made to Barbados on the Tartar (return to England on the New Elizabeth).
1765 Maskelyne appointed fifth Astronomer Royal

H4 examined by committee appointed by Board of Longitude

Harrison awarded half of longitude prize money!!

Board orders Harrison to turn over--

  • H4
  • drawings
  • written explanations of mechanisms 
1766 Harrison ordered to turn over H1, H2, and H3

H1 is dropped and damaged in transit
1767 English watchmaker, Larcum Kendall (1721-1795), was asked to make a copy of H4

Harrison began work on H5, an improved version of H4
1770 Kendall completed H4 copy called K1
  • used by Capt. James Cook on his second voyage (1772-1775)
Harrison completed work on H5
1772 Harrison wrote to King George III
1773 Harrison given £8,750 by special act of parliament
1774 new act of parliament set out terms for winning the prize; all entries must:
  • be submitted in duplicate
  • undergo trials of one year testing at Greenwich
  • be further tested on at least two sea voyages of Board's choosing
1776 death of John Harrison

Rupert T. Gould (1890-1948) and H2.
Gould discovered H1 in 1920 and spent 13 years restoring all the Harrison clocks to their original condition.

     
Go to:
Weekly Readings
1
2
3
4
5
6
7
8
9
10
Lecture Notes
1
3
5
7
9
11
13
15
17
19
2
4
6
8
10
12
14
16
18
20
Riddley Guides
--