CULTURAL HERITAGE SCIENCE AND THE MATERIAL OF MEMORY
The Unwritten Story of Claude Laurent’s Glass Flutes
Lynn Brostoff
Recently I was invited to give a plenary lecture about cultural heritage science for a large annual conference of scientists who use X-ray techniques. Before composing the talk, I thought quite a bit about what cultural heritage science contributes not just to the preservation of historical collections, but to history. This led me to the subject of cultural memory, which could not have been more timely when I gave the talk in August 2020. This blog is based on that presentation and its subsequent publication in Advances in X-ray Analysis.
Cultural heritage science is a relatively young, interdisciplinary field, and has become a core activity within the wider field of cultural heritage, especially as allied to preservation. The inter-relationship of these fields can be seen more broadly in terms of “cultural memory,” an elusive and evolving concept that may be thought of as a kind of nebulous accumulation of humankind’s past knowledge and ideas. Cultural memory is not substantially different than individual memory. Memory itself has no materiality, but of course is intimately linked to physical things. Long-term memory, in particular, involves the conscious recall not only of specific events and facts, but of context, which can be aroused by physical objects, as well as sounds and smells. This is true for individuals as well as groups of people. Part of what makes us human, in fact, is our powerful ability to remember and construct a sense of self through both tangible and intangible materials. In this way we attempt to create a continuum that defines our identity. While an individual’s memory only extends through a generation, cultural memory extends indefinitely, but is subject to the same editing and bias---that is, the same fallibility as individual memory.
When we think about historical collections, we can see them as authentic slices of history, framed by cultural memory. In an age where digital material might be doctored by end-users, this is an especially powerful notion as it relates to physical items. Here cultural heritage science can play a crucial role in maintaining an active dialogue with cultural memory—an important goal for institutions like the Library of Congress—through an analytical approach that provides objective facts and observations about physical items that contribute to narratives. This activity constitutes “technical studies,” in which we use analytical tools to investigate the material of collection items.
One such study was recently undertaken by the Library’s Preservation Research and Testing Division (PRTD) in collaboration with the Music Division, which holds the largest collection of wind instruments in the world, donated in 1941 by Dayton C. Miller (DCM), a physicist and amateur flutist. Dr. Miller was quite forward-thinking in terms of forming a collection meant to represent the diversity of musical traditions from different time periods and cultures all over the world. In this sense, he was consciously adding to cultural memory. Among the DCM collection are 20 examples of rare and exquisite flutes of glass made by Claude Laurent (and his shop) in Paris between 1805 and 1848. Prior to our study, which began in 2014, very little was known about Laurent or his flutes, except for his 1806 patent for “flûtes en cristal.” Due to this wording, it was previously assumed that all of Laurent’s glass instruments were made of “crystal,” a term indicating they contain over 24% lead oxide. Furthermore, most flutes have “Claude Laurent, Brévité,” etched into the silver; the latter word here translates to “patent holder,” implying that they comply with the patent.
Perhaps due to their relative rarity, these objects have often been considered novelties, despite their contemporary praise. Their sound has remained unfamiliar and was found, at least by Dr. Miller, to be unremarkable in comparison to metal flutes. Thus the story of the Laurent flutes was relegated to one of insignificance in the history of flutes. Pictured here are two similar-looking flutes: DCM 375 and DCM 611. On top is the “Madison flute,” so-called because it was gifted by Laurent to James Madison on the occasion of his second inauguration. We know this from Laurent’s letter to the President (in our collection) asking if the flute had arrived safely. This is an amusing detail, if we choose to dwell on it, since it seems that Madison neglected to send a thank you note!
We began the technical study after the curator, Carol Lynn Ward-Bamford, reached out to PRTD to look more carefully at glass opacity that did not seem quite right in some flutes. I was very fortunate to be assigned to this task. Under magnification, we observed micro-cracks on the surfaces of some flutes, including DCM 611, which appears in perfect condition to the naked eye! Pictured here are overlaid spectra we then obtained using X-ray fluorescence (XRF), which uses low power X-rays to produce a series of peaks that each arise from an element detected in the glass. The results clearly disclose two different patterns: one dominated by lead (Pb), and the other by silicon (Si), potassium (K), and calcium (Ca). This signals that Laurent used two basic glass recipes. What is even more surprising is that only two DCM flutes, including the Madison flute, qualify as leaded crystal glass, while the rest are “potash glass,” sometimes known as “bohemian crystal,” which was developed in the 16th century to imitate the famous Venetian cristallo ware, but using potassium-rich ashes from the abundant trees in northern Europe.
This discovery begs the question of why Laurent used two glass formulations throughout his career, especially since they are difficult to distinguish by eye. The Madison flute and DCM 611 flute are perfect examples. The material properties of leaded glass and potash glass are different, first of all. Leaded glass has a higher refractive index, and those flutes would have been a delight to witness being played in candlelight or gaslight, we may imagine. On the other hand, they are quite heavy, which was mentioned as their one negative aspect in the patent examiners’ report. The cut designs of the flutes offer aesthetic appeal, but also lighten the weight of both types of flutes. More significant, however, may be their relative cost to manufacture. By all accounts, leaded crystal glass production was quite expensive, so that the potash glass flutes were possibly made as a business decision.
Whatever the reason, Laurent’s use of potash glass is unfortunate in terms of its inherent instability, especially compared to leaded crystal glass. Silicate glass that does not incorporate enough stabilizers, namely calcium (Ca), may be subject to hydration and subsequent leaching of potassium and sodium. As a by-product, liquid droplets, cracking, and delamination can occur on the glass interior and exterior surfaces, which likely occurred in some DCM flutes from former use and variable storage conditions. If deterioration is severe enough, the glass appears opaque due to light scattering off of damaged areas, although sometimes opacity arises from a rough, original surface.
PRTD’s technical study extended to the application of other non-invasive analytical techniques to fully characterize glass deterioration in the flutes, coupled with historical research. Ultimately the collaboration (partially funded by the NEH) revealed a new story surrounding Laurent’s flutes, as well as practical means to assess Laurent flutes. One aspect that was missing from the study, though, was an understanding of the sound of the instruments. This was contributed in large part by Richard Graef, an accomplished flutist who brought his Laurent flute to LC for a consultation and public performance/discussion in 2020. Mr. Graef related that, after much practice, he succeeded in finding the instrument’s “sweet spot,” and he mesmerized the audience by playing appropriate period music, in which he coaxed the “true and original sound” from the instrument. Mr. Graef expressed his opinion that the Laurent flutes, with their innovative key systems and new material, are underestimated in the evolution of the modern flute.
Results of this study, presented only in small part here, show how technical analyses allow us to gather material evidence that can lay a solid foundation for historical narratives. In the case of the beautiful and alluring glass flutes by Claude Laurent, new information about their elemental composition and condition, plus resurrection of their lost sound, has added both tangible and intangible dimensions to an unwritten story from the history of flutes. Thus cultural heritage science can play a critical role in collaborative studies that preserve artifacts physically as well as metaphysically---as vessels of memory, in which contextualization of the material evidence sheds light on different facets of cultural memory.