Metrology
Page last modified 4/11/2020
See
also Science and Technology for other related timelines.
See also Price-Currencies for historic weights
and measures
See below for Measuring Time
and Dates
21/1/1962 The Meteorological Office started using Centigrade as
well as Fahrenheit.
1960, The 11th General Conference on
Weights and Measures replaced the physical metre with a definition based on
radiation from Krypton-86. In 1983 this was changed again to the distance light
travels in a specified time.
1954, The 10th
General Conference on Weights and Measures added a fourth basic unit, the Kelvin as unit of temperature (see
1889).
1889, The first General
Conference on Weights and Measures established international prototypes for the
metre and kilogramme. Together with the second as unit of time, these became
the three base units of measurement. See 1954.
1848, William Thompson, Lord Kelvin,
established absolute
zero as -273 C.
30/3/1791, The metric system of measurements was proposed in France.
1785, Watt devised the ‘horsepower’ as a unit of work.
30/4/1772, The first
dial weighing machine was patented by John Clais in London.
1761, The first marine
chronometer that was accurate to within half a minute per year was made by Paul
Harrison, England.
25/4/1744, Anders Celsius, Swedish astronomer who devised the Centigrade
temperature scale in 1742, died.
16/9/1736, The German scientist Gabriel
Fahrenheit, who devised a scale of temperature, died.
1720, Fahrenheit invented the mercury thermometer.
27/11/1701, Anders Celsius, Swedish astronomer who devised
the Centigrade
scale of temperature in 1742, was born in Uppsala.
1700, Fahrenheit invented the alcohol thermometer.
24/5/1686. Gabriel Daniel Fahrenheit, the German physicist who invented the mercury thermometer, was born in
Danzig.
1613, Pierre Vernier invented the Vernier Measure, in which a slider is
used to increase the accuract of the distance measured by a factior of ten.
1305, The English acre was
defined by statute as 4,840 square yards.
1101, In England, King Henry VIII
introduced the yard as a measure of
length, the length of his arm.
789, Charlemagne introduced the Royal
Foot as unit of length and the ‘Karlspfund’ as unit of weight, equivalent to
365g or about 13 oz.
2000 BCE. Mesopotamia possessed a standard system
of weights and measures. The Shekel
consisted of 129 grains (8.36 g), and the Mina,
60x as large, were in use by 2400 BCE. By 2000 BCE the Mesopotamians also used
the log (0.541 litres, or 33 cubic
inches), the homer (720 logs), and
the cubit and foot. The cubit was
about 18 inches, the distance from the elbow to the tip of the middle finger.
3100 BCE, Cunieform writing
developed in Mesopotamia; temple records and accounts kept.
Measuring
Time and Dates
1969, The first quartz wristwatches went on sale, in Japan.
1967, The 13th
General Conference on Weights and Measures changed the definition of a second
from 1/86,400 of an average solar day to a number of readiation cycles produced
by a Caesium-133 atom.
1957, The first battery-powered watches went on
sale, in the USA.
1955, The first microwave atomic clock was
unveiled at the National Physical Laboratory, Teddington, UK. It was accurate
to one second every 300 years. By 2020 atomic clocks were accurate to in second
every 300 million years.
1949, The first atomic
clock was made.
1935, Dendrochronology, counting
tree rings to estimate dates, was developed by AE Douglass,
1928, The first quartz crystal
clock was made.
7/7/1923, John Harwood patented the first
self-winding wristwatch. Self-winding watches already existed but they were
bulky fob-watches. The concept was to use a small swinging weight to wind the
timepiece.
21/3/1915, Frederick Winslow Taylor, the inventor of modern scientific
time-management, died.
13/10/1884. Greenwich was adopted as the universal time
meridian from which world longitude is calculated.
13/3/1884, Standard time zones were established in the USA.
20/3/1856, Frederick Winslow Taylor, the inventor of modern scientific
time-management, was born.
1820, The British Royal Navy
ceased to use half-hour sandglasses to keep the time.
24/3/1776, John Harrison, watchmaker and inventor of the chronometer, died in London.
3/9/1752. The date changed this day to 14/9/1752 with the
introduction of the Gregorian Calendar. See 5/4/1753. See also 5/10/1582,
start of Gregorian calendar. Crowds of people protested, believing their lives
had been ‘shortened’ by 11 days (days 3-13 September 1752 inclusive did not
exist). The old calendar had a leap year every 4th year, and
therefore was 365.25 days long.
However the calendar had now got out of step with the real year. The new calendar omitted leap years every
century, unless the year was divisible by 400.
1/1/1752, Officially the first ‘new year’ to fall on 1st
January; previously the new year had begun on 25th March.
8/6/1695, Christiaan Huygens, the Dutch scientist who
invented the pendulum clock, died
(born 1629).
1680, Clocks began to have minute hands. By the
mid 1700s second hands were also in use.
12/1656, The pendulum clock
was invented by Huygens.
1/1/1622, In the Gregorian Calendar, January 1 was declared
the first day of the year, instead of March 25.
1509, The earliest watches were
invented by Peter Henlein of Germany; they were named ‘Nuremberg Eggs’.
1386, The first public clock in
England was installed, at Salisbury Cathedral.
1353, The first known public clock was erected, in Milan,
Italy.
1350, The oldest known alarm
clock was made in Wurzburg, Germany.
1335, The first clock to strike
the hours was made in Milan, Italy.
1325, The first clock with a
dial was installed at Norwich Cathedral, England.
890, Marked candles were used
in England to measure time.
1/1/44 BCE, Julius Caesar introduced the Julian Calendar.
The Julian 365-day calendar was based upon the Egyptian calendar, and replaced
an earlier 355-day calendar used by the Romans. The Roman year began in March,
and the 5th month, Qunitilis, was renamed July after Julius Caesar himself. Augustus
then named the 6th month after himself, too. The Calends was the first day of
the month, and in longer months of 312 days the Nones were on the 7th and the
Ides on the 15th. In shorter months the Ides and Nones fell on the 5th and 13th
days. The Romans also used an 8-day week with the days lettered A to H. For a
while this co-existed with the 7-day week, based on the Sun, Moon and 5 visible
planets. In 321 AD Emperor Constantine ruled that the 7-day week
alone was to be used.
700 BCE, The original Roman
calendar had ten months, plus around 60 days not included in any month. Hence
December, the last month, is named after the Latin for 10; November from 9,
October from 8, September from 7.
159 BCE, The first water clock (clepsydra),
in Rome.
3500 BCE, Earliest sundials
(obelisks) in use, in Egypt.