"The name slug iron or box iron applies to those irons that are heated by inserting a hot slug of metal into the iron cavity or box. The slug heating technique kept the bottom of the ironing area free of ashes and soot which resulted in an improved ironing practice." David Irons, More Irons By Irons, page 22.

Barnes "Swan on Swan" Slug Iron

The "Swan on Swan" Barnes slug iron is the single most desirable and sought after of all American patented irons! It is such a great piece that its true value and appeal is not limited to just iron collectors; it extends to Americana  and Folk Art collectors who want only the best and rarest of pieces. 

The smaller swan at the rear acts as the latch to open the iron.  It works properly, and is a nicely detailed aspect as well.  The iron opens to reveal the original slug.  

Marked BARNES PAT DEC. 11,1877; lettering is under handle. Length = 7 1/2".

Photo courtesy of Larry & Carole Meeker, Meeker's Mechanical Nature Antiques

See also: Irons-Patent Models for the original Barnes "Swan on Swan" patent model.