72 8 POPULAR SCIENCE MONTHLY. 



sand tli of an inch " is heard a hundred times of tener in every shop 

 than "correct within a sixty-fourth or a hundred and twenty- 

 eighth, etc.," and it means not only greater convenience of expres- 

 sion and measurement, but an actually higher standard in pre- 

 cision of workmanship. To the objection, then, that the tendency 

 of mankind is toward a binary rather than a decimal division of 

 units, which is almost the only one offered by Mr. Spencer worthy 

 of serious consideration, we may briefly reply by saying that even 

 granting it to be a fact, it has no bearing whatever on the ques- 

 tions of ratios and relations of units, which is what distinguishes 

 one system from another ; that such a tendency may find ex- 

 pression in one system as well as another, and certainly with in- 

 finitely greater facility in the metric system than that now in use 

 among English-speaking people ; and, furthermore, that the esti- 

 mation of fractional parts by tenths or hundredths is believed 

 by many who habitually work that way to be both easier and 

 more accurate than by halves, quarters, eighths, etc., and as a mat- 

 ter of fact the prevailing tendency is away from the latter and 

 toward the former. 



Mr. Spencer seems to have a painful satisfaction in the fact 

 that in California the "bit" is still used, or was about twenty 

 years ago painful, because he feels obliged to characterize it as a 

 *' retrogression." As already said, it ought not to be necessary to 

 remind him of the slow changes in human customs. Even in the 

 time of John Quincy Adams the word " dime " (which began life 

 as disme) was almost unknown and the coin itself very nearly so, 

 for the shilling in all its multiplicity of forms and values still 

 held place. Even now the shilling, bit, sixpence, " levy," etc., are 

 not unknown in parts of the United States, but their presence 

 serves only to emphasize the enormous superiority of our decimal 

 system of coinage over that which, happily, our forefathers had 

 the courage to throw off. He also expresses surprise that we have 

 a quarter of a dollar, and that he does not see things advertised to 

 sell for one dollar and three dimes or four dimes, etc. 



He has here unconsciously called attention to one of the most 

 important features of a decimal system that, in fact, upon which 

 its great superiority depends namely, the ease with which 

 changes from one denomination to another are made, and the con- 

 sequent almost universal reference to a single unit. Some com- 

 ment on the English money system in respect to this feature will 

 be made later, but in illustration of this remark it may be said 

 that nobody who understands the money system of the United 

 States ever thinks of expressing any given amount in eagles, dol- 

 lars, dimes, cents, and mills, but in dollars only. Everybody, 

 however, can instantly convert any expressed amount into any one 

 or all of these. Compare, for instance, $432'873 and 85 7s. 8f&, 



