ents. 1871--Two cents, 10
cents; three cents, 25 cents. 1873--Two cents, 50 cents; three cents.
50 cents. 1877-'8--Twenty cents, $1.50. These prices are for good
ordinary coins without holes. Fine specimens are worth more.

LEANING TOWER OF PISA.--The leaning tower of Pisa was commenced in
1152, and was not finished till the fourteenth century. Tho cathedral
to which this belongs was erected to celebrate a triumph of the Pisans
in the harbor of Palermo in 1063, when allied with the Normans to
drive the Saracens out of Sicily. It is a circular building, one
hundred feet in diameter and 179 feet in extreme height, and has
fine mosaic pavements, elaborately carved columns, and numerous
bas-reliefs. The building is of white marble. The tower is divided
into eight stories, each having an outside gallery of seven feet
projection, and the topmost story overhangs the base about sixteen
feet, though, as the center of gravity is still ten feet within the
base, the building is perfectly safe. It has been supposed that this
inclination was intentional, but the opinion that the foundation
has sunk is no doubt correct. It is most likely that the defective
foundation became perceptible before the tower had reached one-half
its height, as at that elevation the unequal length of the columns
exhibits an endeavor to restore the perpendicular, and at about the
same place the walls are strengthened with iron bars.

What causes the water to flow out of an artesian well?--The
theoretical explanation of the phenomenon is easily understood.
The secondary and tertiary geological formations often present the
appearance of immense basins, the boundary or rim of the basin having
been formed by an upheaval of adjacent strata. In these formations it
often happens that a porous stratum, consisting of sand, sandstone,
chalk or other calcareous matter, is included between two impermeable
layers of clay, so as to form a flat [Transcriber's Note: The original
text reads 'porus'] porous U tube, continuous from side to side of
the valley, the outcrop on the surrounding hills forming the mouth
of the tube. The rain filtering down through the porous layer to the
bottom of the basin forms there a subterranean pool, which, with the
liquid or semi-liquid column pressing upon it, constitutes a sort
of huge natural hydrostatic bellows. Sometimes the pressure on
the superincumbent crust is so great as to cause an upheaval or
disturbance of the valley. It is o