IV. On the attractive forces of two magnets when their axes are parallel or when the equinoctial of the one lies upon the equinoctial of the other;
V. On the disjunctive and repulsive forces of two or more magnets when the cognomical or inimical poles are applied to each other;
VI. On the attractive forces of the magnet and of iron;
VII. On the influence of the magnet upon ignited iron;
VIII. On the quantity of exhalations from the magnet and their penetration through hard bodies, etc.;
IX. On the various modes of destroying the power of the magnet; and on the chemical experiments made with it;
X. On the friction of the magnet against iron, and on the force communicated from the former to the latter;
XI. On the conjunctive force of the magnet, as exercised upon several pieces of iron;
XII. On the operation of iron and of the magnet upon the mariner’s needle; and on the reciprocal operation of one needle upon another;
XIII. On other methods of making iron magnetical;