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TO THE CANDID READER,

And Student of Magnetic Philosophy,

A Preface.

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When it comes to discovering secrets and investigating the hidden causes of things, more valid reasons exist in more certain experiments and demonstrated arguments than in probable conjectures and the common dogmas of philosophers. Therefore, so that the renowned substance of the great magnet, the common mother [Earth], which is still entirely unknown, and the remarkable and eminent powers of this globe might be better understood, we have proposed to begin from ordinary magnetic, stony, and iron matter, from magnetic bodies, and from the parts of the Earth closest to us, which it is permitted to handle with our hands and perceive with our own senses, to proceed through manifest magnetic experiments, and to penetrate first into the inner parts of the Earth. For after we had seen and examined many things unearthed from high mountains, or the depths of the seas, or from deep caverns and hidden ores, in order that we might finally know the true substance of the Earth, we applied long and great care in investigating the powers of the magnet (powers that are truly admirable, and far more potent than the virtues of all other bodies among us, when the powers of all other fossils are compared). Nor did we find this labor of ours idle and unfruitful, since new and unheard-of properties shone forth to us daily through experimentation, and philosophy grew to such a degree from things carefully observed that we undertook to explain the interior and genuine substance of the earthly globe by magnetic principles, and to point out the Earth (the common mother) to men, as if with a finger, by true demonstrations and experiments that appear manifestly to the senses. And just as Geometry rises from certain very small and easy foundations to the greatest and most difficult things, by which the ingenious mind climbs above the stars: so our doctrine and magnetic science in a convenient order shows first things that are less rare; from those things, more