[…] second, that the white and red man were oil and water, incapable of safely sharing a landscape.

The reason was to allow the newer backspaceable Teletypes and their code-compatible derivatives to represent the international character sets more readily.

to saw boards or planks (i.e. to saw logs or timber into boards or planks)

..and I'm just musing that you taxpayers in the United States are now paying me to shitpost on alt.slack.