requisiteness

For I find that Beguinus, and other Assertors of the Tria Prima, pretend to make out by such a way, the requisiteness of their Salt, Sulphur and Mercury, to constitute mixt Bodies, without taking notice of any necessity of an Addition of Water and Earth.

After he had done there, he and I into the garden, and walked; and the greatest of our discourse is, his sense of the requisiteness of his parting with his being Treasurer of the Navy, if he can on any good terms.