MAGNETICK Motions

In Book 1, I talked about:

• the magnet-stone and its variety
• its poles and its known faculties
• the properties of iron
• a magnetick substance common to iron and the earth

Here I explain magnetical motions, and their fuller philosophy.

These motions are incitements of homogeneal parts either among themselves or toward the primary conformation of the whole earth.

Aristotle admits only 2 simple motions of his elements, from the centre and toward the centre.

Lightweight ones upward, heavy ones downward.

In the earth, there exists one motion only of all its parts towards the centre of the world,—a rude and inert precipitation.

But what of it is light, and how wrongly it is inferred by the Peripateticks from the simple motion of the elements, and also what is its heavy part, we will discuss elsewhere.

The motions of magnetick bodies is different.

These are present in the earth and in all its homogenic parts also.

They harmonize with the earth, and are bound up with its forces.

I observe 5 movements:

1. Coition (commonly called attraction), the incitement to magnetick union

2. Direction towards the poles of the earth, and the verticity and continuance of the earth towards the determinate poles of the world.

3. Variation

This is a deflexion from the meridian, which I call a perverted movement.

4. Declination

This is a descent of the magnetick pole below the horizon.

5. Revolution or circular motion

Jofrancus Offusius makes out different magnetick motions:

1. Towards a centre

The first is not always to a centre, but exists only at the poles in a straight course toward the centre, if the motion is magnetick.

Otherwise it is only motion of matter toward its own mass and toward the globe.

2. Towards a pole at 77 degrees

The second toward a pole at 77 degrees is no motion, but is direction with respect to the pole of the earth, or variation.

3. Towards iron

4. Towards loadstone

The third and fourth are magnetick and are the same.

So he truly recognizes no magnetick motion except the Coition toward iron or loadstone, commonly called attraction.

There is another motion in the whole earth, which does not exist towards the terrella or towards its parts; videlicet, a motion of aggregation, and that movement of matter, which is called by philosophers a right motion, of which elsewhere.