1. The "Positive," from the Electric Cleaner Company of Chicago, is another black box on wheels, looking like something out of a science fiction novel. Published in the June, 1909 issue. Click big.
Something that looks a little bit more like we would expect today, the Duntley could be picked up and carried by your maid. From the May, 1909 issue.
The history of product design is the subject for someone else's blog, but you can't avoid thinking about it. Pretty soon the maid would give way as chief domestic tool user to the homeowner herself, a victim of economic necessity and a whole new customer demographic.