But this oddness belongs to other numbers also (pentad, heptad, &c.).
In 1820, he added to the last a pentad, so that the whole list amounted to sixty-five.
Five, or the pentad, is everything; it stops the power of poisons, and is dreaded by evil spirits.
Nitrogen in the triad condition in the amines is far less poisonous than in the pentad condition.
There is something to ...