the
most prolific crops. Liebig and Johnstone, the two great agricultural
chemists, have demonstrated beyond any controversy that the
resuscitation of worn-out soils depends materially upon the addition of
phosphate of lime; and hence the application of bone-dust, which is a
phosphate of lime, and guano, which contains the latter ingredient with
the ammoniacal salts in combination, of which at the present day
100,000 tons are annually consumed by the farmer, along with the
artificially prepared superphosphate of lime, are well known, but do
not belong here.
LEPIDOLITE.
This
mineral derives its name from the Greek language, from its scaly
structure; it occurs massive, presenting an aggregate of minute,
shining, flexible scales or hexagonal plates ; it has a splintery
fracture ; a glistening and pearly lustre; is translucent on the edges;
its colors are lilac, rose-red, pearl-gray, greenish-yellow, and blue ;
it is scratched by glass, and yields to the knife; has a specific
gravity of 2.81 ; is fusible with ease into a transparent globule. It
is found in granite and primitive lime, in Monrovia, France, island of
Elba, Corsica, Sweden, and in the United States, in Maine, New
Hampshire, Vermont, and Massachusetts. It is cut in Europe for various
ornaments, such as plates, vases, snuff-boxes, &c, and will, -I
trust, at some future day, be more extensively used in jewelry; for
there are some variegated specimens of a peach-blossom color, and very
fine granular structure, which are extremely beautiful.
MICA.
This mineral occurs crystallized, in six-sided tables and oblique rhombic prisms, and massive; also, disseminated;
