The defence must be active; then the attack would cease, and the French people, seeing its failure, would demand a reform of the system imposed on them; the other nations suffering under it would follow their example, if indeed the Teutonic peoples did not begin the reaction.
Modifications would be demanded, rendering the metric system less inconvenient for manufacturers, for trade, for the everyday business of life.
The metric standards would be retained, but the decimal system would be optional, left principally for scientific purposes. The divisions and multiples would be in harmony with the customs of each people, usually in sexdecimal series.
For France, the _système usuel_ of Napoleon’s compromise would be revived. Incomplete a century ago, it could be rendered complete by the following arrangement of the metric system, suitable both to Northern and to Southern France.
1. The metre to be divided optionally either into 3 feet of 12 inches, or into 4 spans of 9 inches or 12 digits; 2 metres to be a toise and 10 toises a perch; 100 toises or 10 perches to be a centenié (furlong) and 800 toises or 8 furlongs a mile = 1741-3/4 yards. The meridian mile would be 926 toises or 9-1/4 cables.
2. Land to be measured by the square toise, 1/25 of an are; 1600 square toises to be an arpent of 16 vergées metriques or boisselées, each 10 toises square, = 4 ares.
3. The livre, = 500 grammes, to be divided commercially into 16 ounces of 8 drachms; and for medicinal purposes, the drachm to be 8 oboles of 8 grains. Grammes and decimal fractions of a gramme could be used for scientific purposes.
4. The hectolitre would be divided sexdecimally, into 4 boisseaux, of 4 gallons = 6-1/4 litres. The litre would be divided into 2 setiers or chopines, 4 half-setiers, and 32 ounces.
The equivalence with imperial measures would be approximately:
1 Metre = 1-1/10 yard. 1 Mille = 1 mile. 1 Vergée = 1/10 acre. 1 Arpent = 1·6 acre. 1 Livre = 1-1/10 lb. 1 Litre = 9/10 quart.
Similar arrangements could be made in other countries, the units being made in accordance with the old custom of the people, but always on a metric basis so that international conversion of measures would be easy and accurate.
With this suggestion of compromise, of _entente cordiale_, instead of constant aggression by the French system against that of the British dominions and America, I close the last chapter of my work. I took to it twelve years ago for useful occupation in the leisure of approaching retirement from active life in a great seaport. But as I carried out my design I found the verge of the wide subject recede with every advance I made; every fresh field I worked showed another field beyond. A renewal of life for study, travel, observation, would be needed to enable me to carry out at all completely this history of the human mind in one of its most interesting and important aspects. But age warns me to bring my work to a close, leaving its correction and completion to younger men. Yet I hope I have been able to show the principles of unity and of diversity; and apparent confusion becomes clear when the keys of metrology are at hand. The trend of the human mind is always the same; for weights and measures are a part of the daily life of every man and woman. The rise of measurement, the naturalisation of weights and measures brought by commerce, even by conquest, when they are found convenient, the varieties caused by changes of circumstance, the deflections under the constraint of ill-advised rulers, the effect of long custom in reconciling to new standards if they can only be arranged conveniently, the shifts by which they can be made endurable, the tendency to resume the old trend along another path—all these traits of human nature are shown in this study. One thing is certain, that a wise government sanctions the measures which fit its people; its business is to maintain unity in the inevitable variety; and it should distrust the pretensions of science to dictate to men and women, to trade and manufacturers, the measures they shall use. Whether in theocratic ancient Egypt or in revolutionary modern Europe, science is a good servant of Humanity, but a bad master.