First edition, separately-paginated offprint of this early publication on electricity and magnetism.
It was in this work that Ampère (1775-1836) first presented his famous rule for determining the direction of deflection of a magnetized needle placed near an electric current.
A complete copy with the last leaf (table and errata) which is often missing.
The 'Exposé' is an offprint from the Supplement to the French translation of Thomas Thompson's System of Chemistry.
references: Mottelay [p.482 : "a very valuable treatise"].