198 POPULAR SCIENCE MONTHLY. 



gible to those of other nations. Evidently moved by the desire 

 for human welfare at large, scientific men have been of late years 

 "urging that the metric system should be made universal, in the 

 belief that immense advantages, like those which they themselves 

 find, will be found by all who are engaged in trade. Here comes 

 in the error. They have identified two quite different require- 

 ments. For what purpose does the man of science use the metric 

 system ? For processes of measurement. For what purpose is 

 the trader to use it ? For processes of measurement plus processes 

 of exchange. This additional element alters the problem essen- 

 tially. It matters not to a chemist whether the volumes he speci- 

 fies in cubic centimetres or the weights he gives in grammes are 

 or are not easily divisible with exactness. Whether the quanti- 

 ties of liquids or gases which the physicist states in litres can or 

 can not be readily divided into aliquot parts is indifferent. And 

 to the morphologist or microscopist who writes down dimensions 

 in subdivisions of the metre, the easy divisibility of the lengths 

 he states is utterly irrelevant. But it is far otherwise with the 

 man who, all day long, has to portion out commodities to cus- 

 tomers and receive money in return. To satisfy the various 

 wants of those multitudes whose purchases are in small quanti- 

 ties, he needs measures that fall into easy divisions and a coinage 

 which facilitates calculation and the giving of change. Ask him 

 to do his business in tenths, and he will inevitably be impeded. 



" But you forget that the metric system is approved by many 

 mercantile men, and that its adoption is urged by the chambers 

 of commerce." No, I have not forgotten ; and if I had I should 

 have been reminded of the fact by the fears now expressed that 

 our commerce will suffer if we do not follow in the steps of 

 sundry other nations. The fears are absurd. French and Ger- 

 man merchants, when sending goods to England, find no diffi- 

 culty in marking them or invoicing them in English measures. 

 And if English merchants imply that they are too stupid to 

 follow the example in a converse way, they can scarcely expect 

 to be believed. Surely the manufacturers who supply them with 

 piece goods will make these up in so many metres instead of in so 

 many yards, if asked to do so ; and similarly in all cases. Or, if 

 not, it needs but a table on the wall in the clerk's office, giving in 

 parallel columns the equivalents of quantity in English denomi- 

 nations and French denominations, to make easy the needful in- 

 voicing and labeling. But it is not on this flimsiest of reasons 

 that I wish chiefly to comment. The fact here to be specially 

 emphasized is that merchants are not in the least concerned with 

 the chief uses of the metric system. Their bales and chests and 

 casks contain large quantities — dozens of yards, hundredweights, 

 gallons. They do not deal with subdivisions of these. Whether 



