ZETA.

Zeta Herculis, periodic time, eclipse

of, 398 ; light, 402.
Zinc, seleniate of, effect of tempera-

ture on its crystals, 107; sulphate
of, its crystals boiled in alcohol,
108.

electricity communicated to
plates of, 220.
Zodiac, the, signs of, change in their

positions, 80.
Zone of constant temperature in the

atmosphere, 119; laws of storms
in the temperate and torrid, 127,
128 ; of spots on the sun's surface,
its breadth, 224; of constant tem-

ZOOPHYTES.
perature below the earth's crust,
228 ; comparative unequal distri-
bution of land in temperate and
torrid, 244 ; of fixed stars, 385 ;
of stars nearest the sun, 390 ; ne-
bulous, 416 ; of nebulous patches,

417; of meteoric nebulæ, 423.
Zones of instability of planetary orbits,
21.

of temperature in the ocean,
101.

of vegetation on the Peak of
Teneriffe, 250.
Zoophytes, specific distribution of,

254.