3 legged cast iron chair question

I was given this old painted cast iron chair. i had it sandblasted and will be painting it to restore it's beauty. there is a lot of detail (fish, birds, vines, flowers, grape clusters on the legs). it has three legs and is very heavy. it was in the boston area. does anyone have any information about this interesting find? maker? age? value? the sandblasting did a terrific job and only cost 65 dollars to do.