There is something transcendental in the idea of this measurement of the earth in order to find a measure for daily life. It was an immense undertaking. But the conception seems to have been vast rather than practical. There is reason to believe, from later labors, that there was a serious error in the work. Thus, the distance of 10,000,000 metres from the equator to the north pole, established by the French observers, is too small by 935 yards, according to Bessel,--by 1,410 yards, according to Puissant,--and by 1,967 yards, according to Chazallon. Sir John Herschell also testifies with the authority of his great name against the accuracy of this result. If there be an error such as is supposed, then the metre ceases to be what it was called originally, one ten-millionth part of the distance from the equator to the north pole. Even assuming that there is no error, and that the metre is precisely what it purports to be, yet it is not easy to see how the artificial standard can be corrected by recurrence to the standard in Nature. The massive work originally undertaken will not be repeated. The astronomers of France will not verify the accuracy of the bar of platinum, which is the artificial standard, by another scientific enterprise, requiring years for completion. Therefore, for all practical purposes, the metre is really nothing else than a bar of platinum with a certain length preserved in the archives of France. It is not less arbitrary as a standard than the yard or foot, and it can be perpetuated in practice only by distribution of exact copies from the original bar, which is the assumed metre. I have thus explained the origin and character of the metre, because I desire that the admirable system founded on it should be seen actually as it is. To my mind, it gains nothing from the theory which presided at its origin. Its unit is not to be regarded as a certain portion of the distance between the equator and the north pole, but as an artificial measure determined with peculiar care. Had the same or any other unit been selected without measurement of the earth, the metric system would not have been less beautiful or perfect. * * * * * Look now at the system. The metre, which is assumed to be one ten-millionth part of the distance from the equator to the pole, is, in fact, 39⅓ inches, or 39.37 inches, in length. It is especially the unit of _length_; but it is also the unit from which are derived all measures of weight and capacity, square or cubic. It is at once foundation-stone and cap-stone. It is foundation-stone to all in the ascending series, and cap-stone to all in the descending series. The unit of _surface measure_, or land measure, is the _are_, from the Latin _area_, and is the square of ten metres, or, in other words, a square of which each side is ten metres in length.