Tin cans?

According to dubya yes man, Alberto Gonzalez, President George Washington authorized electronic surveillance on a "far broader scale" than the current president. This little gem was first brought to my attention by the Phenom, and I have since found references to this factoid on the web (so it has to be true).

What sort of electronic surveillance were they capable of in the late 18th century? Tin cans and string? Did they have tin cans? Perhaps Johnny Tremain fashioned silver bowls for use in wire tapping. I wonder how effective such surveillance was in those days? Did people plotting the overthrow of the newly formed government/country not notice the bowl with long string running up the street that was propping up the window?

What if they actually fashioned silver or metal "ears" and gave them to people to mount in their homes as art, and thus giving rise to the saying "the walls have ears" ? Maybe they trained insects to wander about on the floor, record conversations and then report back by an elaborate morse code? That could be the source of the saying "this place is bugged."

Sometimes, I wonder how these people who seem to have some power manage to dress themselves in the mornings.