ps only on the Surface of Conductors.--1
figure

The Colson Telephone.--3 engravings

The Meldometer.--An apparatus for determining the melting
points of minerals

Touch Transmission by Electricity in the Education of Deaf
Mutes.--By S. TEFFT WALKER.--With 1 figure

V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By
C.F. HOLDER.--With 2 engravings

How Plants are reproduced.--By C.E. STUART.--A paper read
before the Chemists' Assistants' Association

VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure

* * * * *

THE USE OF IRON IN FORTIFICATION.

Roumania is thinking of protecting a portion of the artillery of the
forts surrounding her capital by metallic cupolas. But, before deciding
upon the mode of constructing these formidable and costly affairs, and
before ordering them, she has desired to ascertain their efficacy and
the respective merits of the chilled iron armor which was recently in
fashion and of rolled iron, which looks as if it were to be the fashion
hereafter.

[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.]

The Krupp works have recommended and constructed a cupola of
casehardened iron, while the Saint Chamond works have offered a turret
of rolled iron. Both of these recommend themselves by various merits,
and by remarkably ingenious arrangements, and it only remains to be seen
how they will behave under the fire of the largest pieces of artillery.

[Illustration: FIG. 2.]

We are far in advance of the time when cannons with smooth bore were
obliged to approach to within a very short range of a scarp in order to
open a breach, and we are far beyond that first rifled artillery which
effected so great a revolution in tactics.

[Illustration: FIG. 3.]

To-day we station the batteries that are to tear open a rampart at
distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch
cannon that arms them has for probable deviations, under a charge of 20
pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16
inches in direct fire and 8 inches in curved.

The weight of the projectile is 88 pounds, and its remanent velocity at
the moment of impact is 1,295 feet. Under this enormous live force, the
masonry gradually crumbles, and carries along the earth of the parapet,
and opens a breach for the assaulting columns.

[Illustration: FIG. 4--STATE OF A