The principle on which names should be given is sufficiently clear. The names should simply answer the natural questions: "How long is it? How big square? How heavy?" etc.
To illustrate by long measure—the base-unit is now called the metre—"How long is that?" is the first question. A pace, a long step, a stride, would answer the question; probably, in England and America, despite all objections, a new yard, or a long yard, is the best name. The new would be dropped in due time (as in new style and old style), and the name becomes simply yard.
To proceed with the table. Each and every unit in each table should have its own strong, independent name, instead of a name referring to the base-unit, so called. The actual relation between the units is important; but to express this in the name is worse than superfluous, it is a mere incumbrance. There is no danger of forgetting the decimal scale.
The metric tables provide names for—
1000, 100, 10, 1, 10, 100, 1,000, 10,000 metres.
Some of these we would omit, and perhaps provide others not given, beginning with the 10000 part, for microscopic uses.
What should the name be? It should suggest the length intended, say, a hair's-breadth, or a leaf's-thickness; soon, by shedding, a hair or leaf.
The name of the 1000 part? Still suggestion—say, a pin's-breadth (soon, a pin), a straw's-breadth, a narrow braid, a coin's-thickness, or a card's or knife-blade's. The words "breadth" or "thickness" would serve the purpose of explanation at first, and then shed, leaving only pin, straw, braid, knife-blade, card, etc.
Some such name would serve—not, millimetre in Latin and Greek; not, even metre-thousandth in Greek and English; not, any name expressing a numerical relation to some other unit. If any numerical relation at all, not to a unit at 1,000 removes. Finally, not a fractional relation, if any, but one expressed by a whole number. All these negative limitations are full of matter.
The next name—the 100 part—might be nail's-breadth, nail.
The next, now decimetre, hand.
Then, the new yard, or long yard, finally to become yard.
The fifth unit, 10 metres, half-chain. Really no name needed.
100 metres stone's-throw; bow-shot throw, cast, shot.
1,000 metres a short mile, new mile. An accidental association would make the word kile serve. The learned would know the Greek derivation; the unlearned would remember it by the rhyme. Numerous illustrations occur, equally casual. The objection is not to Greek, but to the want of some familiar association, no matter how trifling.
10,000 metres a great league, or double league.
Observe that each unit thus named is as much a base-unit as any other.