The Metric System

Abstract

I NOTE a call from Mr. John W. Evans, in NATURE for December 5, 1895, for the use of the metric system in meteorology. If this means the substitution of the metre for the yard, there can be no serious objection except this. In meteorological studies ˙01″ of air pressure is an extremely convenient limit, and in most inquiries only two figures are needed. On the other hand a millimetre (˙04 inch) is altogether too large a limit, and one-tenth m.m. is too small. The labour of writing, averaging, and studying with the metric scale will be at least one-third greater than with the common inch scale to the same degree of accuracy. It is a very great pity that the French, in looking for a convenient length to divide into a thousand parts, did not take up the already existing yard, which is nearly the same as the metre. Yard ÷ 1000 = (metre ÷ 1000) − ˙004 inch. The amount of confusion that would have been saved is almost incalculable.