This quantity of heat is the same as that already found in equation (3), but for the small area BFC, which is **negligibly** small in the limit compared with H.

If these equations could be assumed to hold when H is indefinitely small, it would follow that has a finite initial value, from which there would be no appreciable deviation in fields so weak that bH was **negligibly** small in comparison with a.

Coulomb, 2 however, by using long and thin steel rods, symmetrically magnetized, and so arranged that disturbing influences became **negligibly** small, was enabled to deduce from his experiments with reasonable certainty the law that the force of attraction or repulsion between two poles varies inversely as the square of the distance between them.