I'm not sure if I'm answering my own question here: I think the device (black machine just to the left of the Eden washing machine) is an early blood pressure monitoring mechanism. I found an article re: "the wave writer", invented in 1847 by German physiologist Carl Friedrich Wilhem Ludwig. Here's the link to the article, which contains a nice drawing of the object. It looks a little like a more modern version of the machine in the article. Anyone else care to comment?

http://www.lifesciencesfoundation.org/events-item-654.html

Another benefit of resistance dimmers is that they worked just as well on DC as on AC.

Autotransformer and Thyratron (or Thyristor) dimmers only work with AC.

Note the plug at the end of the vacuum cleaner cord screws into a lamp socket. Although the type of outlets we know today existed before 1923, it would be about another decade before they became common enough for appliances to be sold fitted with plugs that were bladed rather than threaded.

The Dim-A-Lite was undoubted a rheostat,
inefficient and heating itself internally.
The good news?
It wouldn't create noise in nearby electronic equipment.
You DID have a lot of electronic equipment, no?
www.edisonian.com/p011f001.htm

Everywhere I look there is something interesting! Are those Statue of Liberty fixtures on the railing posts at the bottom of the stairs? I want those!

This was definitely the shop of a technology buff. Today he would have a dual CPU with 6 cores each and plenty of RAM to boot. I would like to have worked in this shop.

That leftside cabinet just full of radio parts! And near the radiator, what looks to be a modern rotary spark-gap transmitter. Just the thing to show the local Ham!

This ad for the Eden washing machine from April 1923 shows a slightly different model than the one in the photo. My grandmother in Toronto had a similar looking machine in her basement, and the area was definitely off limits to us as kids.

Let me at those model trains !