Declination and Direction on Superphysics

Declination

Tue, 20 Feb 2024 00:00:00 +0000

In due course we have now come to that notable experiment, and remarkable motion of magnetick bodies dipping below the horizon by their own rotatory nature.

By the knowledge of which is revealed a unity, a concordancy, and a mutual agreement between the terrestrial globe and the loadstone (or the magnetick iron), which is wonderful in itself, and is made manifest by our teaching.

Declination

Tue, 20 Feb 2024 00:00:00 +0000

Diagram of declinations of the magnetick needle, when excited, in the various portions of the sphere, and horizons of the earth, in which there is no variation of the declination.

An indicatory instrument, showing the degrees of declination from the horizon

Tue, 20 Feb 2024 00:00:00 +0000

Take a terrella of the best strong loadstone, and homogeneous throughout, not weakened by decay or by a flaw in any parts; let it be of a fair size, so that its diameter is six or seven digits; and let it be made exactly spherical. Having found its poles according to the method already shown, mark them with an iron tool; then mark also the æquinoctial circle. Afterwards in a thick squared block of wood, one foot in size, make a hemispherical hollow, which shall hold half of the terrella, and such that exactly one half of the stone shall project above the face of the block.

The length of a versorium convenient for declination on a terrella

Tue, 20 Feb 2024 00:00:00 +0000

Declination being investigated on the earth itself by means of a declination instrument, we may use either a short or a very long versorium, if only the magnetick virtue of the stone that touches it is able to permeate through the whole of its middle and through all its length. For the greatest length of a versorium has no moment or perceptible proportion to the earth’s semi-diameter.

The proportion of declination to latitude, and its cause

Tue, 20 Feb 2024 00:00:00 +0000

I have already discussed:

the making of an instrument for finding declination
the causes and manner of declination
the different degrees of rotation in different places
the inclination of the stone
an instrument indicating, by the influence of a stone, the degree of declination from any horizon
needles on the meridian of a stone, and their rotation shown for various latitudes by their rise toward the perpendicular.

What are the causes of the degree of that inclination?

Diagram of the rotation of a magnetick needle

Tue, 20 Feb 2024 00:00:00 +0000

In the more elaborate diagram a circle of rotations and a circle of declinations are adjusted to the body of the earth or terrella, with a first, a last, and a middle arc of rotation and declination.

Demonstration of direction, or of variation from the true direction with declination

Tue, 20 Feb 2024 00:00:00 +0000

Demonstration of direction, or of variation from the true direction with declination by means of only a single motion in water, due to the disposing and rotating virtue.

Floating versorium shows both motions.

The essential magnetick activity sphærically effused

Tue, 20 Feb 2024 00:00:00 +0000

Discourse hath often been held concerning the poles of the earth and of the stone, and concerning the æquinoctial zone; whilst lately we have been speaking about the declining of magneticks toward the earth and toward the terrella, and the causes of it.

Magnetick force is animate, or imitates life

Tue, 20 Feb 2024 00:00:00 +0000

In many things, magnetick force surpasses human life, while this is bound up in the organic body

Aloadstone is a wonderful thing in very many experiments, and like a living creature.