This is the porcelain relative of the Miva T5-S "spook" power distribution insulator, this was also called "portafusibile" which means "fuse holder". The thin wire (3 or 4 strands of #30 ga wire) acted as the incoming power fuse. These "spooks" could also hold a knife switch, or fuse clips, in order to accomodate a more standard style glass cylindrical fuse. This is approximately 1920-1930 vintage, and typical house power distribution was 240VAC @ 5 amps. No "energy hog" appliances, just lighting, and maybe radios and fans. HEating, cooking, etc, were powered with gas, wood or coal... Dimensions are about 8cm tall, 6 cm base diameter.

I'lpost a non-flash photo over in "foreign insulators"