Dating horsehair furniture
I thought the same thing, until going to the link provided by Finn, and saw that that particular mattress company uses something they call "curled horsehair": had a 19th-century sofa reupholstered the other year, and the upholsterer gave me a thorough documentation, with photographs, of what she had done.She mentions the original stuffing material as being "hair," which I have ever reason to assume was horsehair.Sooner or later, if a piece has wheels on it, someone is going to try to roll it across the carpet in order to clean around or behind it and then the problem starts.The 1-inch diameter wheels common on most 20th pieces are really not built for speed.
Tightly woven, it gives a glossy black, hard-wearing surface. As a stuffing it is luxurious and rare, partly because its springiness and durability are second to none for upholsterers: a seat stuffed with horsehair can last up to centuries.
It all seems to be in surprisingly good shape (I'm assuming, because it was in my great grandmother's house, that it's probably late Victorian, something around there), but I'm also assuming I should replace it. Horsehair is apparently still available (perhaps from the glue factories? For an example, yesterday one of the blogs on the New York Times website had this post about a mattress factory in the Bronx that is shown using it to make a new mattress.
Under that is some light batting stuff and then some sort of piping tacked around the edge, I assume to give it a nice edge. It's a firm kind of cushioned stool (well, it is now - I assume it's meant to be firm).
On newer pieces, the tag may be on or underneath removable cushions or the skirt of a couch.
Determining the manufacturer also determines the potential date range of the piece.