Many of the words coined by him are now obsolete, but one at least, "circuit," still remains in use.
In 1746, a French scientist, Louis Guillaume le Monnier, bad made a circuit including metal and water by laying a chain half-way around the edge of a pond, a man at either end holding it.

One of these men dipped his free hand in the water, the other presenting a Leyden jar to a rod suspended on a cork float on the water, both men receiving a shock simultaneously.

Watson, a year later, attempted the same experiment on a larger scale.

He laid a wire about twelve hundred feet long across Westminster Bridge over the Thames, bringing the ends to the water's edge on the opposite banks, a man at one end holding the wire and touching the water.

A second man on the opposite side held the wire and a Leyden jar; and a third touched the jar with one hand, while with the other he grasped a wire that extended into the river.