The Importance of Standards of measurements:
How about wood and metal rulers? I think my dad's slide rule was ivory and bamboo--inaccurate?Very cool. This is why we have NIST in the US. It's also why plastic rulers (and plastic slide rules from back in the day) can't always be trusted for high precision measurements. There's too much thermal expansion/contraction going on.
I would guess that the important parts would have been made of ivory, which is far less hydrophilic than wood and thus less prone to expand on humid days and contract on dry ones. Metal is probably the best choice. It's still not perfect though, just less prone to problems than other materials.How about wood and metal rulers? I think my dad's slide rule was ivory and bamboo--inaccurate?