I am relpying to Sue Maltby's request for information on this topic and I am posting it to the list for those who might enjoy techno-trivia. What came to be known as the Bower-Barff Process is actually a modification of the ancient processes of forming stable oxidation films on metals by the use of thermal and reduction/oxidation athmospheres. Charcoal blueing of gun components, springs, and fine instuments is an example of this process. What came to be known as the Bower-Barff Rustless Process was invented by Professor Fredrick S. Barff of Kilburn, England, who published his results in 1877. The process was subsequently modified by George Bower who modified Barff's process to an industrial scale. In the Bower-Barff Process cleaned iron or steel bars were heated to a bright red color (1700 F) in special furnaces where super-heated steam would be inroduced. This produced a "skin" of stable magnetite (Fe3O4) and some Wustite (FeO) oxides which cocooned the iron, making it relatively impervious to rapid oxidation (rusting). Later improvements to the process utilized hydrogen and carbon monoxide athmospheres which allowed for complete conversion of the ferrous surface to magnetite. This meant that the process could be performed on a large industrial scale with consistent results and the Bower-Barff Process was patented in 1881. After it's widespread adoption for use in architectural ironwork the process came to be know as "Barffing". "Barffing is so called from the name of its discoverer; and its purpose is to render the surface of metallic article treated, resistant to acids and impervious to humid oxidation. Iron and steel that have been properly Barffed will not rust. The process belongs in no sense to the chemical laboratory, and it requires no particular scientific knowledge or technical skill for its success. Highly polished work retains its finish after the process, although the treatment changes the shinning polish to a dark slate color. But working parts, such as sliding and rubbing surfaces, retain their smoothness, and work as freely as before the process; plugs, valves, and stems for cocks, gates, and faucets, for instance, working just as smoothly as though they had not been Barffed." -Brannt, W.T., ED. The Metal Workers Handy-Book of Receipts and Processes, 1896, pps. 297-298 . For those who want to read about this process in-depth, along with descriptions of other nineteenth century architectural metal finishes which were investigated during the restoration/conservation of the Rookery in Chicago, Ill., USA, I highly recommend the following paper: "Conservation of Architectural Metalwork: Historical Approaches to the Surface Treatment of Iron" by Frank G. Matero, in Ancient & Historic Metals: conservation and scientific research, David Scott, Jerry Podany, Brian B. Considine, Editors, The Getty Conservation Insititute, 1994, ISBN: 0-89236-231-6 (pbk.) This book also contains papers which range from the restoration of the monument to Marcus Aurelius to the use of gold foil, strip, and wire in the iron age of Southern Africa. It is a must for conservators and curators who work with ancient and historic metals collections. Dave David Harvey Conservator of Metals & Arms Colonial Williamsburg Foundation P.O. Box 1776 Williamsburg, VA 23187-1776 USA voice: 804-220-7039 e-mail: [log in to unmask]