Terry Simpson wrote in USMA 22940:
Joseph B. Reid wrote:Look at the BIPM brochure. Table 6 lists [...] metric units Table 10 list other non-SI units, but which are indisputably metric: Table 9 units [...] are definitely metric.I hope you aren't getting frustrated with discussing this. I don't see anywhere that suggests that the units in Table 6 to 10 are units of the modern metric system. We agree that they are non-SI. You say 'indisputably' and 'definitely' metric but I am (I am sorry to say) disputing it.I read: "the International System of Units (SI), which is the modern form of the metric system." and I conclude: 1. SI unit = unit of the modern form of the metric system 2. Non-SI unit = not a unit of the modern form of the metric system The whole text of the brochure is consistent with this interpretation. Where is the text that says otherwise? I appear to be so out of line with the rest of you that I need you to be patient and walk me through step by step. -- Terry Simpson
Does Terry mean that the units that I listed in USMA 22931 ceased being metric when SI was defined? They indisputably were once "metric" but they did not make the list of SI units. They were used throughout the world before SI was defined. The establishment of SI required the definition of new units.
SI unit Replacing Date
------- --------- -----
pascal bar, torr, poise 1971
joule erg 1946
newton dyne 1946
tesla gauss 1960
weber maxwell 1946
lux phot 1960
gray rad 1975
sievert rem 1985
Joseph B. Reid
17 Glebe Road West
Toronto M5P 1C8 Telephone 416-486-6071
