D, Each of the four segment-cells gives rise by division to a small pellucid cell.
The St Lawrence varies only a few feet in the year and always has pellucid bluish-green water, while the Mississippi, whose tributaries begin only a short distance south of the Great Lakes, varies 40 f t.
E, The cap of small cells has increased in number by repeated formation of pellucid cells in the same way, and by division of those first formed.
Successive nations perchance have drank at, admired, and fathomed it, and passed away, and still its water is green and pellucid as ever.
In consequence of its low refractive and dispersive power, colourless pellucid fluor-spar is valuable in the construction of apochromatic lenses, but this variety is rare.