These irons were used --before electricity. The one on the left was heated with natural gas. On the right is a "self heater" into which hot coals were placed, the conventional "iron" that was placed on the stove--many households had a few of those so one would heat while the other was in use; at the bottom are a brass iron that had a metal core that was heated separately in a stove and an early 20th century one in which the handle detaches whilst the iron heats.
Considering that people ironed absolutely everything and starched the salt out of the most simplest garments.... and all the big skirts, the heirloom sewing that was standard, the ruffles, the collars, the pleats.....Owww!
I can only imagine the burns as I am pretty clumsy. However, in light of going green, these irons may prove useful in a post-peak oil world. Keep an eye out at those antique shows. There could be a reproduction market.....
Anyhow, new post at my site all about ironing in the construction process! Sewing Scholar