534 



SCIENCE. 



[N. S. Vol. XIX. No. 483. 



THE METRIC SYSTEM. 



In the current issue of Science (March 

 4) Mr. Alfred C. Lane has presented some 

 useful hints with a view to facilitating the 

 popular adoption of the metric system in 

 America. His chief points are the adop- 

 tion of the metric ton as the standard of 

 mass, the definition of the standard pint 

 as the volume of a half-kilog-ram of water 

 under standard conditions, and the defini- 

 tion of the foot as the length of the edge 

 of a cube whose capacity is 62.5 pints. 

 This last definition is said, in an appended 

 note, to be not essential to the scheme. 



In any system of metrology the unit of 

 length is that to which all other units are 

 finally referred, unless these are so arbi- 

 trary as to preclude the use of the word 

 'system.' The essentials of any desirable 

 system are simplicity and consistency. An 

 ideal system is that developed a century ago 

 in France and now employed by all scien- 

 tific workers, but not yet popular with the 

 masses in English-speaking countries. The 

 problem of conferring popularity upon it 

 is one that will require many years yet for. 

 its solution. 



Whatever may be the form taken by 

 legislation in England and the United 

 States, the people can not be compelled to 

 adopt nomenclature that is thrust upon 

 them as a substitute for that to which they 

 have always been accustomed. The nomen- 

 clature must be simple in order to secure 

 adoption; it must be at least fairly in 

 harmony with old customs in order to win 

 favor. For many centuries past the foot 

 has been by far the most popular unit of 

 length, though the range of variation in 

 its value has been 165 per cent, of the 

 smallest magnitude to which the name was 

 applied. In like manner the pound has 

 been the popular unit of weight, with as 

 many as 235 variations in value. The use 

 of these names in different languages is 

 popularly maintained, even in countries, 



like France and Germany, where the metric 

 system is legally established. 



If the metric system is ever, to become 

 popular in the United States it must be 

 through the medium of such legislation as 

 will give us its substance with as little as 

 possible of its nomenclature. Its essential 

 features are: 



1. A decimal relation between all the 

 units employed. 



2. A direct and simple relation between 

 units of length and mass. 



In view of the strong influence of old 

 customs we can not expect a new system 

 to be inaugurated that is exclusively deci- 

 mal. If the people are accustomed to 

 binary or duodecimal subdivision they will 

 hold to it in spite of legislation. All of us 

 are disposed to do what we find easiest. 

 Nor is there much reason to expect that all 

 units of length and mass will be discarded 

 except those connected by the simplest re- 

 lation. Ideas may differ as to what is 

 simplest, and in any case there will be a 

 survival of what the populace finds fittest, 

 irrespective of the prescriptions of theory. 

 The introduction of the metric system can 

 be accomplished only by some sort of com- 

 promise, through which old names may be 

 retained while the values of the correspond- 

 ing magnitudes are slightly modified for 

 the sake of simplicity. 



Everybody understands that by a process 

 of selection the once chaotic British system 

 has been becoming simpler. Many units 

 that were in use a half century ago are now 

 obsolete, though the inconvenient relation 

 between those still surviving is bad enough 

 and incapable of much improvement. By 

 still further excision, by adoption of a few 

 names and values from the metric system, 

 and by such modification in existing values 

 as will produce no great inconvenience, we 

 may quite reasonably hope for such prac- 

 tical adoption of a decimal system as to 



