Metric and Wilkins compared – not quite deja vu

A feature of the metric system, which distinguishes it from customary systems, is the use prefixes for decimal multiples and submultiples as well as the use of symbols for units. These were not part of Wilkins’ proposals of 1668. Roddy Urquhart compares these with the modern metric system (SI).

I have finally had time to read through Wilkins’ proposed units of measure. If we substitute Wilkins’ base unit, the Standard for the metre it looks like we have the following relationships:

mutiplier        Wilkins’ unit     metric equivalent     symbol

1000               Mile                   kilometre                   km
100                 Furlong             hectometre                hm
10                   Pearch               decametre                  dam
1                      Standard           metre                           m
0.1                  Foot                    decimetre                   dm
0.01                Inch                   centimetre                  cm
0.001             Line                    millimetre                   mm

1                      Bushel               cubic metre                 m3 or 1000 litres
0.1                  Peck                   100 litres                    0.1 m3                                        0.01               Quart                  10 litres                      0.01 m3                                                            0.001             Pint                     litre                             L

100                 Tun                     100 tonnes
10                    Thousand          10 tonnes
1                       Hundred            tonne                          t or Mg
0.1                   Stone                  100 kg
0.01                Pound                 10 kg
0.001              Ounce                kilogram                      kg
0.000 1          Dram                  hectogram                   hg
0.000 01        Scruple              decagram                     dag
0.000 001      Grain                 gram                             g

I am astonished to see a lot of ideas from the modern metric system (SI) here. However although Wilkins manages to use decimal for different orders of magnitude he exhausts the more traditional vocabulary for describing units. Any larger or smaller he would run out of words! This leads me to another thought.

One of the real achievements of the metric system defined in 1790 was their use of prefixes. This idea allowed a very systematic way of consistently describing larger and smaller quantities and was superior to the reuse of traditional terms by Wilkins. That principle was extended by the British Association for the Advancement of Science in 1874 when they proposed mega- and micro- prefixes which were adopted in the metric system. Prefixes have been subsequently greatly extended since then by international agreement.

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2 Responses to Metric and Wilkins compared – not quite deja vu

  1. Pat Naughtin says:

    Dear All,

    Roddy is correct in that John Wilkins did not include the prefixes with his original 'universal measure'. He also did not include any reference to the word, 'metre' or to any of its derivatives (I think that 'metre' came from the translation of the English words, 'universal measure' into the Italian 'metro catholico', probably by Burratini in 1675).

    However what John Wilkins did describe was a system that:

    * was decimal

    * was international

    * had a standard length (of about 997 millimetres)

    * used measures based on a 'Natural Standard' that could be reproduced in any nation of the world.

    * was intended to be related to time (as it is today)

    * was coordinated so that the measures of length, area, volume, mass (he called it weight and based it on distilled rain water), and time could be all interrelated within one system.

    * was based on a 'Universal Measure' (that became known as the metric system after 'universal measure' was translated into the Italian, 'metro catholico' by Burattini, seven years later, in 1675).

    * was universal in that it was intended for all human activities.

    I think that these are enough benefits and features to say that John Wilkins invented the metric system.

    By the way, I think that the two metric prefixes (deci and centi) were first suggested by Prieur in the 1790s and that these were further developed by Van Swinden from the Netherlands before the contributions of the British Association for the Advancement of Science (BAAS) in the mid-1800s.

    Pat Naughtin

  2. George Carty says:

    Shouldn't it be 'metro catolico', or has the Italian language reformed its orthography since 1675?

    (Now there are no THs or PHs in Italian, only Ts and Fs.)


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