For USA readers - You'll find that after you've converted to the metric system you won't give a monkeys whether an inch is 25.4 or 99.9mm. You'll completely forget what an inch is (as we've done here) and the sooner the better!!!
Mike Joy Perth, Australia ----- Original Message ----- From: "Joseph B. Reid" <[EMAIL PROTECTED]> To: "U.S. Metric Association" <[EMAIL PROTECTED]> Sent: Thursday, August 01, 2002 4:16 AM Subject: [USMA:21460] Re: Inch | Markus Kuhn asked in USMA 21452: | | >Jim McCracken wrote on 2002-07-31 13:45 UTC: | >> The inch was not set at 25.4 millimeters centuries ago, but in the | >> 1950s. | > | >Was setting the inch to 25.6 mm or 25.0 mm seriously discussed as an | >option at this or at any earlier opportunity? Is the rationale for the | >choice of 25.4 mm for the inch documented somewhere in more details, as | >well as the history of previous definitions for the inch? | > | >When was the inch defined in the US for the first time with an accuracy | >of better then 0.1 mm? the practice of length measurement with a | >relative error below 1% surely must predate the 1950s significantly ... | >even centuries ... | > | >Markus | | | The imperial yard was measured against the metre in 1897 and found to be | 1 yard = 0,914 399 metre, or 1 inch = 25,399 972 mm | | The American yard was defined in the Mendenhall Order in 1893 by | 1 yard = 3600/3937 meter, or 1 inch = 25,400 050 8 mm. | | The International Organization for Standardization (and perhaps the | preceding International Standardizing Asspciatioin) adopted an | international inch of 25.4 mm. | | Canada in 1950? decided to adopt the ISO inch. | | In 1959 a conference of English-speaking countries adopted the ISO inch of | 25.4 mm. | | Joseph B.Reid | 17 Glebe Road West | Toronto M5P 1C8 Tel. 416 486-6071 | |
