1901, there were as many as eight different standard
gallons. Brooklyn, NY, recognized four different legal
measures of the foot. About 50% of tested food scales
were wrong, usually favoring the grocer. Firehoses from
neighboring cities did not fit together, causing tragedies
like a 1904 Baltimore fire that razed 70 city blocks.
Today, thanks in part to NIST, most consumers take it
for granted that weights and measures are accurate and
that products will fit together.