Identification of 1850s Brown Zinc Paint Made with Franklinite and Zincite at the U.S. Capitol Author(s): Frank S. Welsh Source: APT Bulletin, Vol. 39, No. 1 (2008), pp. 17-30 Published by: Association for Preservation Technology International (APT) Stable URL: http://www.jstor.org/stable/25433934 Accessed: 25/12/2009 10:57 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=aptech. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Association for Preservation Technology International (APT) is collaborating with JSTOR to digitize, preserve and extend access to APT Bulletin. http://www.jstor.org Identification of 1850s Brown Zinc Paint Made with Franklinite and Zincite at the U.S. Capitol FRANK S. WELSH Research and analyses disclose that Introduction white lead and application of lead-based brown, zinc-based primer used on paints. Recent investigations of interior paints The findings of this project add not 1850s cast iron at the U.S. Capitol in the 1850s House and Senate of wings to the of the construction of the United States have revealed only history contains made from the Capitol more pigments the U.S. Capitol but also, and for the first time the original brown zinc crushed ore of franklinite and zincite significantly, to the history of zinc-paint paints that were made by the New manufacture and the use of minerals as advertised by the New Jersey Zinc Zinc inNewark, New Jersey Company architectural in this as a paint pigments Jersey. Used factory-applied, rust Company. in the mid-nineteenth on country century. inhibitive primer the cast-iron door Much has been written about zinc and window enframements installed at paints and the Franklin-area mines; however, the this contains unusual Capitol, paint until the at the the that were made discovery Capitol, pigments by crushing use of crushed franklinite and zincite ore franklinite and zincite ore from the as an pigments in architectural paint celebrated Franklin and Sterling Hill was never studied in detail. Identifica mines in Sussex County in northwestern tion of these minerals can be used as a New Jersey. reliable benchmark for and/or The New Zinc was dating Jersey Company a authenticating layer. The results one of the first manufacturers of zinc paint that future studies oxide and zinc-based architectural and suggest published concerning zinc pigments should include industrial paint inAmerica. In addition a more accurate of their manu to the also made at least history white, company facture franklinite and zincite in seven other colors of zinc using paint, espe the mid-1800s in America. cially brown, for use principally as primers on metals but also for finish coats on exterior wood surfaces. The ore Identification of Brown Zinc Paint at the from which American-made zinc paint Capitol was first manufactured was discovered The Capitol was constructed in the late in Franklin, New in the cen Jersey, eigh eighteenth and early nineteenth ore teenth century. The contained many was turies. It greatly expanded between minerals of different colors and compo 1850 and 1867 with the addition of sition, the primary ones, including north and south wings and a new cast zincite and which occur ? franklinite, iron dome all designed by architect nowhere else on earth. Thomas U. Walter and overseen by The of the Franklin-area history engineer Capt. Montgomery C. Meigs. mines and the zinc extracted from the The extension project, as it was ore are linked. The mines two inextricably called, comprised the wings that and innovative manufacturing processes housed new House and Senate chambers to gave birth the zinc pigment, zinc new cere plus offices, meeting rooms, paint, and ready-mixed-paint industries monial spaces, grand staircases, and in America. The nineteenth-century elegant corridors (Fig. 1). Fireproofing incentive for the and manufac mining was a great concern to Walter and oth turing industries to develop zinc oxide after the British burned Fig. 1. The United States Capitol, 1867, looking ers, especially as an alternative white for southwest, as the 1850s extension project pigment the Capitol in 1814. Consequently, architectural and industrial was designed by Thomas U. Walter was nearing paints Walter elected to trim all of the new completion. The north (Senate) wing is in created the health by significant prob door and window openings with cast south (House) wing is in back foreground; lems associated with the manufacture of or iron casings enframements (Walter ground. Courtesy of the Architect of the Capitol. 17 18 APT BULLETIN: JOURNAL OF PRESERVATION TECHNOLOGY / 39:1, 2008 and called them Meigs window and ments. These projects started in 2002 in ings and ornaments in order to get the door The door dressings). enframements Senate Office S-312 with the Office of thickest layer evidence, since paint tends in the were basement manufactured by the Senate Curator and continued in to accumulate in crevices and corners. the Baltimore firm of as a Hayward, Bartlett 2004 part of window-shutter survey The samples from the various fea and but the basement win tures were Company, throughout the Capitol with the Office analyzed microscopically, dows and all door and window en of the Curator of the Architect of the initially in a loose fractured state under framements well as all (as ornamental Capitol. In 2005 the project culminated the stereomicroscope and afterward in and in the cross ceilings gallery fronts) upper with taking additional samples from mounted sections. All samples floors were manufactured, starting in door and window enframements in exhibited the same brownish gray, oil 1855, by Janes, Beebe and Company of other offices and public spaces in order based, shop-prime paint layer(s). The New York.1 to distribute the locations of samples color of the paint varies little from of the more than to Many 600 cast-iron throughout the first, second, and third sample sample and is very close to door and window enframements have floors in both wings. The basement the Munsell color reference value of detailed ornamental on moldings their rooms, dome, and ceilings were not 2.5 YR 6/1. This color is described in are so architraves, all of which finely sampled. the National Bureau of Standards Color executed that when finish painted they This last stage was unusual in that it Name Charts as Light Brownish Gray. resemble carved and on a exquisitely molded focused prime paint layer, in con Stereomicroscopical studies show wood Walter have even trast to most (Fig. 2). may paint analysis, which that this brownish gray paint layer that Beebe and a specified Janes, Com typically concentrates on finish paint contains number of very colorful and enframents be before rare - pany primed ship layers and their colors. It is that unusually large (0.1 0.25mm), coarsely as he did with ment, the castings for the pigments in architectural paints are ground yellow, orange, red, and black in even more Congressional Library 1853, giving analyzed, and so for those pigment particles. Their size, color, and instructions "to the with can be as a paint castings that categorized shop primers. appearance in paint film were totally two coats to before shipping, prevent This project focused specifically on the unfamiliar. Upon initial inspection they rust and to a foundation for unusual did not share lay good color of and the pigments used any characteristics of paint the ornamental painter."2 to make the brownish gray oil primer on pigments heretofore seen or described in three the door Recently, during separate paint and window enframements in standard artist-pigment references (Fig. investigation and analysis projects Senate Office S-312 and on all other 3). the throughout first, second, and third door and window enframements subse To identify these unknown pigments floors of the interior of the north (Sen quently sampled. and, subsequently, their source and and south brown ate) (House) wings, Numerous sites from door and win fascinating history of manufacture, they zinc was identified for the first dow in rooms were paint enframements eight in analyzed microscopically and time as the on the mid-1850s both were sam to primer wings investigated and instrumentally document their optical cast-iron door and window enframe pled. The selected spaces and features characteristics and chemical composi are representative from each floor and tion.3 wing. They included H-128, window enframements; H-218, window en framements; H-319, window enframe ments; and the west grand staircase third-floor door enframements in the south wing (House side) and S-128, window enframements; S-211, door 'mm^?M?^'^?^M' enframements; S-312, door enframe east ments; and the grand staircase third-floor door enframements in the north wing (Senate side). In a many cases, sample of the cast iron substrate could not be extracted with the paint layers intact, as is typi cally done with wood and plaster.