The Basis of Our Measuring System

The measuring system used for scientific work affords a means of making physical measurements with great precision and accuracy. The best measurements can be made of the quantities taken for the basis of the system. A decrease in both accuracy and precision arises in measuring quantities which are related to them in a complicated way. The standards which fix the magnitudes of the units on which the system is based appear to be very constant. Some improvement in the system may be obtained by substituting physical constants for these standards. This has already been done for the standard of temperature, and it can be done advantageously for the standards of length and time; but there seems to be no way to replace advantageously the standard for mass.