ceramic insulator?

I found this digging in an 1800s dump its looks like an insulator,but everything that came out of this dump is from the 1800s.If it is an insulator what was it used for.It stands 1 1/2 inches high 1 5/8 inches wide.The hole goes right through.
                               Thanks Gary

it is a insulator for an electric fence

The short answer is "yes" it is an insulator.  Your 1800s dump could easily have items from then on into later years.  These small insulators were used in installing electricity into homes when electrical power first came available.  There would be 2 separate insulated wires running side by side and attached to the insulator by laying each wire into a separate groove and tied off.  These were also used on telegraph poles for the wire runs.  Early home radios required an antenna wire to be run outside and up a pole for good reception--at least out in the country.  If the folks couldn't afford real insulators, they'd break off the neck of a glass bottle and use it for mounting the radio antenna.

And, as stated above, they were / are used for electric fences.

dad used to say don't p on the wire but why listen

they were also used in the attics of old houses to separate the hot wire from the nuetral

indoor insulator