As some of you know, I love historic furniture. So I found a few things on eBay I thought folks may be interested in:

Among other things is a depiction of an invalid chair: http://cgi.ebay.com/RARE-1855-adv-KING-SON-Various-Elegant-CHAIRS-NewYork_W0QQitemZ370331277540QQcmdZViewItemQQptZAntiques_Furniture?hash=item563976d8e4

Cottage furniture depicted: http://cgi.ebay.com/RARE-1855-adv-HALEY-WARE-CO-cottage-furniture-Phila_W0QQitemZ370331278550QQcmdZViewItemQQptZAntiques_Furniture?hash=item563976dcd6

Parlor furniture depicted: http://cgi.ebay.com/RARE-1855-adv-EDWIN-A-SMALLWOOD-Furniture-Boston_W0QQitemZ370331277161QQcmdZViewItemQQptZAntiques_Furniture?hash=item563976d769

Sincerely,
Emmanuel Dabney
Atlantic Guard Soldiers' Aid Society
http://www.agsas.org

I think the swivel bit is at the back and therefore the person pushing would steer. As a therapist, I think the knobs are for scooting fwd in the chair and getting from sit to stand. That is if the foot rest is removable. (better be  )

Not to be confusing the swivel chairs with the fact that the wheel at the back of the wheelchair swivels - I would call that a large caster.

I have plenty of experience with wheelchairs, too (my husband is in one). It's always hard to say from an illustration, but take a closer look. The knobs on the arms are attached to bent rods, which go down and attach directly to something near the front wheels - axles? I'm pretty sure those front wheels are steerable, although probably within a rather limited range. I would love to see one of those in person!