Pitch.
A kind of bitumen. Noah covered the ark with pitch inside and outside. Genesis 6:14. The ark in which the infant Moses was put, was likewise thus rendered waterproof. Exodus 2:3. Among God's judgements on the earth the streams are turned into pitch, and the land into burning pitch. Isaiah 34:9. Different words are employed in the Hebrew of Genesis 6:14 from the other passages. Noah was to pitch (kaphar, 'to cover,' often translated 'atonement') the ark with pitch (kopher, translated 'ransom') as if to teach that Noah and those with him could be saved only by being covered with a ransom, and which would introduce them to a new earth.