Mike Rendell

I was intrigued to see that someone at Oxford University is suggesting that our use of Imperial measurements (feet and inches, pounds and ounces etc) should be re-considered because of their links to Empire. How woke. How unutterably, depressingly woke. Apparently the ‘history of modern measurement is tied deeply to the idea of the ‘Empire’ and Imperial standardisation.’ But to me, the point is: which Empire do you want, French or British – or even Roman? Both France and Britain have used a whole raft of different measuring standards, many of them deriving originally from Roman measurements, and both countries started to review and standardise those measurements during the second half of the Eighteenth Century.

The French were quicker off the mark when modernising their standards. Prior to the French Revolution you might have measured distances by the ‘toise’ (roughly two metres). But the French also used the foot, divided into twelve inches, in turn divided into twelve ‘lines’. But the French ‘foot’ was not the same as the English ‘foot’, and its length varied from province to province. As for weights, the French adhered more-or-less to Roman measurements. So you had the pound, divided into sixteen ounces. Except that sometimes it was made up of twelve ounces, each divided further into eight gros, each of 72 grains. Whole units were generally divided into fractions – halves, quarters, eights and sixteenths.

Goodness knows how you traded goods when you had no idea of the size and quantity you were getting!

Neither the French nor the English had moved to embrace decimalisation – largely because it took until around 1500 for Arabic numerals to become prevalent. Back in 1585 a Flemish mathematician by the name of Simon Stevin had brought out a book called ‘De Thiends’ explaining how Arabic numerals could be divided into tenths by the simple expedient of using the decimal point. That book was translated into both French and English, the latter being called ‘Disme: The Art of Tenths Or, Decimall Arithmetike: Teaching how to Performe All Computations Whatsoeuer, by Whole Numbers Without Fractions’.

The English version came out in 1608,  and Stevin realized that his research could mean that weights, measurements and even the currency could all be re-jigged so that it was divisible by ten.

Nearly half a century later, enter Oliver Cromwell. He rather liked the idea put forward by the Oxford mathematician Robert Wood that the English pound should be divided into ‘tenths, hunds and thous’. Cromwell kept the pound – he re-named it the Broad – but also had a gold coin worth fifty shillings minted, worth ten times the amount of the existing five-shilling crown. Both were struck from dies made by Thomas Simon on the presses of the Frenchman Pierre Blondeau. Cromwell never got around to minting a coin for the tenth of a Broad and when Charles II was crowned he immediately went back to the coinage of his Stuart forebears.

But by the eighteenth century both international trade and science were beginning to suffer because of the lack of standardisation – French chemists could not communicate their ideas to their English, Swedish or German counterparts because each was using slightly different measuring standards. You needed conversion tables for a whole range of things – from temperature, to weight, from dimension to cost. The British accepted that reform was needed and parliament considered the whole topic in July 1789. M.P. Sir John Riggs Miller put forward a proposal of a system based on length of a seconds pendulum at the latitude of London.

To explain: back in the previous century a French parish priest by the name of Gabriel Mouton had proposed a natural unit based on the size of the Earth. This was the length of a minute (a sixtieth of a degree) of longitude, to be called the ‘mille’ and divided into tenths, hundredths and so on. One thousandth of a mille was called the ‘geometric foot’ and Mouton suggested that a pendulum of this length should be set up in his home town of Lyon. Naturally enough, the English were never going to accept a French calculation based upon a French city – they wanted the pendulum to be based on the Greenwich meridian. There was apparently an attempt by the French to persuade Britain to join forces, but the overture was rejected. Talleyrand had suggested to the French National Assembly that it should make a direct approach to the British government, but on 1 December 1790 the Foreign Secretary informed the French Ambassador in London that the proposed collaboration was ‘not practicable’.

In the event, the British parliament dropped the idea: Sir John Riggs Miller lost his seat in Parliament and the French were free to bring in their ideas on standardisation on their own.

It was with this background to decimalisation that the new United States adopted a decimal currency (ie the dollar and the cent) soon after Independence. In France the National Assembly gave way to the National Convention. In 1794 the Convention decided that the basic unit of measurement should equal to 3 feet 11.44 lines, and was to be named the ‘metre’, from the Greek ‘metron’ (measure). Logic would suggest that multiples and divisions should also have a Greek prefix. But no, the decision was made to use Greek for the multiples (deca and kilo) and Latin for the sub-divisions (deci and milli). So we got kilometres and millimetres. The cubic decimetre became the’ litre’ and the weight of a cubic centimetre of water at its temperature of maximum density was named the ‘gramme’.

The French went further in deciding that the calendar needed a bit of an overhaul. Twenty-four hours in a day was far more than anyone wanted: ten was quite sufficient. The year was kept at 12 months, but each month consisted of three ‘decades’ of 10 days. That meant that an additional five days would be added at the end of each year (six in leap years), The French public never accepted the reduction in hours but the new calendar remained in use until 1805. Years were to be dated from the revolution, so Year Three was 1794-5. I can well remember going round ancient Egyptian tombs, and being surprised at the graffiti left by French antiquarians who poured into the ancient archaeological sites during the French occupation of Egypt between 1798 and 1801. Somehow you don’t expect to see graffiti from 1798 listing the names of French visitors, describing their presence in ‘Year Seven’ but there you go!

The change in French measurements started to be rolled out after 1799. It was announced in 1804 that it was to be applied throughout the nation with immediate effect. However, in practice the metric change took many years. The changes were set out in a book by A Macon entitled ‘Instruction sur les mesures déduites de la grandeur de la terre.’  This was quickly circulated and re-printed throughout France.

Rather more rapidly, the decimalisation of the French currency was accepted readily, not least because the new-fangled franc was much the same size and value as the old livre. The livre had been divided into twenty sous whereas the new franc, containing five grammes of silver, was divided up into hundredths i.e. centimes.

As for Britain, there was an ongoing move towards standardisation and in 1824 the Weights and Measures Act established standardised Imperial units for length, mass and volume, replacing what had been known as Winchester Standards, operating since medieval times. It also introduced two new basic standard units, the Imperial standard yard and the troy pound, and these units were imposed throughout the British Empire.

Under the new rules one Imperial gallon was defined as the volume occupied by 10 pounds of distilled water at 62 degrees Fahrenheit (i.e. 160 fluid ounces). The Americans, being different, went off and decided that their liquid gallon would weigh 128 fluid ounces. Previously the English had used different sizes of gallon when measuring wine and ale, as opposed to dry gallons used for measuring wheat and grain. Indeed there was the extraordinary situation where  in Scotland barley, oats and malt were sold in units equivalent nowadays to thirteen litres – whereas wheat, peas, beans and meal were sold in units of  around nine litres. To make things even more confusing, both sets of unit went by the same name – the peck. Nowadays we only remember the peck from the Peter Piper rhyme, but I gather that in the States you can still buy a peck of apples. Mind you, there were also three different weights going by the title of ‘pound avoirdupois’ during the reign of Queen Elizabeth. All very confusing!

Dry goods such as grain were generally measured by the bushel, with sub-divisions of pecks, gallons and quarts. For Scrabble-lovers, how about the fact that two pecks were called a kenning and four pecks made a firlot? In 1496, a law of King Henry VII instituted the bushel that would later come to be known by the name “Winchester”. So, what of the old Winchester Standards? Well, they appear to date back to pre-Conquest times, when Winchester was the royal seat of Saxon kings such as King Edgar. He kept the ‘prototype’ standards at Winchester and although they were brought up to London after the Norman Conquest the connection with the name ‘Winchester’ remained.

One of the earliest attempts to define the gallon, bushel and quarter is the Assize of Weights and Measures. It is unclear when this was enacted – probably some time between 1250 and 1305. It is listed under Ancient Statutes of Uncertain Date and it states: By Consent of the whole Realm the King’s Measure was made, so that an English Penny, which is called the Sterling, round without clipping, shall weigh Thirty-two Grains of Wheat dry in the midst of the Ear; Twenty-pence make an Ounce; and Twelve Ounces make a Pound, and Eight Pounds make a Gallon of Wine; and Eight Gallons of Wine make a Bushel of London; which is the Eighth Part of a Quarter.

The Winchester Measure of a bushel was mentioned by name in a statute of 1670 entitled An Act for ascertaining the Measures of Corn and Salt. The Winchester bushel contained eight gallons. Coopers were commissioned to produce standard containers of the precise size – nineteen and a half inches in diameter and nine inches high, usually made of ash and bound with copper or iron hoops. Each town would commission its own ‘quality control’ measure. The istDibs site has a picture of one such measure.

It was stated as having been made by John Savidge of Tower Street in London. Apparently Savidge specialized in making these standard measures and took out a patent in 1744. This size of bushel lasted until 1824 when a larger bushel, of ten rather than eight gallons, was introduced.

I cannot find out much about Savidge but there is a reference in a newspaper of 1753 suggesting that he was declared bankrupt, so perhaps there wasn’t an immediate demand for his measures. Tower Street – now known as Great Tower Street – was a prosperous area leading to the Tower of London, forming part of the processional route used by monarchs on their way to their coronations. The istDibs site give a date for the bushel measure as 1770 and the Walpole Antiques site have a similar one, for Cambridge, dated 1779.

Ah well, the 1824 the Weights and Measures Act certainly applied throughout the Empire: by its own admission it introduced ‘Imperial’ measures so perhaps, in the interests of wokeness, we should ditch it and go back to the Egyptian measure of the cubit. Or perhaps we should abandon both Fahrenheit and Celsius as being  in some way ‘contaminated’ and adopt the Kelvin unit of measuring temperature. Wikipedia has this wonderful explanation of the advantages of  the Kelvin: “It  has the philosophical advantage of being independent of any particular substance. The unit J/K is equal to kg⋅m²⋅s⁻²⋅K⁻¹, where the kilogram, metre and second are defined in terms of the Planck constant, the speed of light and the duration of the caesium-133  ground-state hyperfine transition respectively.’  Couldn’t have put it better myself – and in case you are wondering, in  the kelvin scale pure water freezes at 273.15 K, and it boils at 373.15 K. Much more satisfactory than boring old Celsius, and with the added bonus that it is not in the slightest bit tainted by Empire….

 

• (I am grateful to the Johnson Matthey Technology Review for its explanation of the French metrication movement).