XLIII Scientific Instrument Symposium - SIC 2024

Session Chair: Giorgio Strano (Museo Galileo, Italy)

Preservation actions on instruments for electrical measurements by means of in situ physico-chemical investigations
Author: Emma Angelini
Co-Author: Margherita Bongiovanni
A preservation campaign is going on in Politecnico di Torino on the important collection of instruments and equipments for electrical measurements coming from the Department of Physic, and from the laboratory for the Superior School of Electronics, founded by Galileo Ferraris in 1888, and ceded to the National Electronic Institute Galileo Ferraris when settling it in 1934. The collection includes a wide range of instruments employed for didactic purposes and research from 1920 to 1960: electrometers, voltmeters, amperometers, galvanometers, valve and battery testers, power supplies, converters, electrical analysers, etc.

These multimateric artefacts are in different conditions of conservation and the definition of tailored conservation strategies cannot ignore the knowledge of the chemical composition of the constituent materials as well as the one of the superficial layers, for example varnish, lacquers, corrosion products, etc..

The preservation campaign is carried out by means of in situ non invasive analytical techniques, X-ray fluorescence (XRF) spectroscopy and Raman spectroscopy, performing the measurements with portable instruments, as well as electrochemical characterizations by means of electrochemical impedance spectroscopy (EIS), to assess the protective effectiveness of the corrosion patinas or of the coatings on the artefacts.

Different corrosion morphologies related to the different metallic materials and to the different exposure conditions to the environment have been found among the instruments of the collection, rather common phenomena of galvanic corrosion resulting from the coupling between alloys of different nobility, as copper-based and iron-based alloys or gilded elements. have also been observed. Three case studies will be described in detail.

Management of Polychlorinated Biphenyls in Ingenium’s Scientific and Technological Collections
Author: Skye Marshall
Co-Author: Erin Secord
Polychlorinated biphenyls (PCBs) are a highly regulated class of organic compounds with negative toxic effects on human health and the environment. PCBs can be found in a variety of scientific, technological and industrial objects including computers, X-ray units, microscopes, sensors, and other electronics. Despite their prevalence in collections containing modern manufactured objects, PCBs in heritage institutions is only recently understood. To contribute to the field of knowledge related to PCBs in collection objects, Conservators at Ingenium - Canada’s Museums of Science and Innovation developed a risk management approach to the identification and remediation of of artifacts that may contain PCBs, This process was implemented during an ongoing large-scale collections move to a new purpose-built facility, resulting in over 1500 objects identified as containing PCBs or possibly containing PCBs.
The Ingenium PCB approach was holistic and innovative. PCB risks were managed with consideration of Regulators’ requirements, collection value, health and safety, and resource availability. This presentation will discuss Ingenium’s PCB management practices and the next steps in increasing awareness of PCBs in the Heritage sector.

All Charged Up and Nowhere to Go: Preservation Issues for Batteries in Collections
Author: Erin Secord
Batteries are common in technological and modern collections and present a number of health and safety and preservation risks that should be well understood and managed.   Many historic objects contain, lead-acid nickel-cadmium, and alkaline batteries, while Lithium-Ion batteries may be found in objects manufactured after 1991.
Batteries are a form of stored energy, usually involving metals and electrolytes that can cause harm to human health, the environment, and collection objects. Ingenium has identified, preserved and managed over 400 battery objects and is undertaking collaborative research into the safe long-term storage of Lithium-Ion batteries.
This presentation will outline the preservation issues related to batteries in collections, Conservation treatment case studies for lead-acid and alkaline batteries, recent Lithium-Ion Battery Safety research undertaken by Ingenium’s Senior Research Fellow, and our next steps in understanding and preserving batteries in Museum collections.

Study and restoration of two microscopes from Geneva's Museum of the History of Science
Author: Mathilde Sneiders
The study and restoration of two microscopes from Geneva's Museum of the History of Science has revealed recurrent and visible alteration to scientific instruments.

The first microscope with its wooden case probably dates from the end of the 18th century. Residues of old white cleaning products are visible on the brass parts and in the interstices, some wooden parts are broken.
The second microscope, by Pillischer, dates from the 19th century. The varnished brass is corroded.
The CleanLaB project developed at the HE-Arc in Neuchâtel, proposes to treat varnished brass using active agents such as traditional complexing agents or greener alternatives (for the user or the environment) to stabilize degradation and reduce the corroded appearance under the varnish.

Tests and treatments were carried out using gels and playing with different parameters (pH, application time, type of active agent, viscosity, etc.). The aim was to obtain a satisfactory and uniform appearance for the varnished brass using the cleaning methods and products recommended following studies carried out in recent years by Julie Schröter and the HE-Arc of Neuchâtel.

Session Chair: Trienke van der Spek (Teylers Museum, Netherlands)

Songs of the Bowhead Whale: tracing the origins of marine mammal acoustic science in the Arctic through a collection of hydrophone artifacts
Author: Tom Everrett
In August, 1970, American biologist Roger Payne released “Songs of the Humpback Whale.” It would go on to become the highest selling environmental album in history and contribute to a flurry of popular and scientific interest in whale vocalizations. Over the course of the 1970s, marine mammal acoustics would develop from a niche area of inquiry into an established scientific discipline, attracting researchers from around the world. At the heart of this work was the humble hydrophone: a microphone adapted for underwater listening and recording. It is with this tool that scientists learned to listen to marine wildlife, record their acoustic environments, and develop improved means for tracking their movement across vast oceans. In Canada, Chester Beachell was among the first to develop hydrophone technology for documentary and marine wildlife applications. Through the 1970s, while working as an engineer at the National Film Board of Canada, he developed hydrophone equipment for a variety of purposes and locations: from the warm waters of the Caribbean to the frigid waters of the Canadian High Arctic. In this presentation, I will describe what Beachell’s artifacts and archival documents might tell us about the development of marine mammal acoustic science in the 1970s – a field in which he remains virtually unknown today. I will focus specifically on Beachell’s work in the Northwest Territories and northern Alaska between 1972 and 1974, during which time he participated in scientific expeditions, designed bespoke hydrophone equipment for use in extreme conditions, and captured what might be the first ever recording of a Bowhead whale’s “song.”

Interpreting color and measuring light: Precision in diabetic glucose analysis
Author: Elizabeth Neswald
For much of the 20^th century color indicators were used to show urine sugar and, later, blood glucose levels to diagnose and monitor diabetes. Whether Benedict’s solution in a test tube or glucose oxidase on a test strip, shades of color corresponded to glucose concentration. Despite numerous attempts to create color standards for these tests, which were primarily used by physicians and patients, they could, at best, be described as semi-quantitative. Difficulties with reproducing colors for the scales, gaps between color scale “units”, and the effect of ambient lighting pointed to problems that arose from making color material. The most intractable problem was the variability of human visual perception. Colors and eyes were not precise enough tools of measurement. In addition, the question of what was precise enough changed, as approaches to diabetes management demanded ever tighter glucose control.

In the second half of the 20th century, Instruments based on photocells were introduced into biochemistry and physician and patient testing regimens in part in response to these problems. This paper shows how dissatisfaction with these semi-quantitative methods and distrust in the visual capacity of test users drove both the adoption of photoelectric registration methods and the automation of the testing process. The aim was to replace both measurement techniques and testing regimens that were considered imprecise and human-error-prone with methods deemed more “objective”. Through photoelectric colorimeters, reflectance photometers, and automatic analysis apparatus, human agency was removed from the testing and interpretation process.

Suppression of Self-Noise in Stepping Correlator Channel Sounders: A Cautionary Tale
Author: David G. Michelson
Accurate characterization of the wireless environment has long been key to designing and deploying effective wireless communications systems. The introduction of the sliding correlator channel sounder by Cox in the early 1970’s helped to transform such characterization from an art into a science. By the 1990’s, advances in digital technology made it possible to introduce the stepping correlator channel sounder and thereby overcome some key limitations of the earlier instrument. While most of the behaviour and limitations of the stepping correlator channel sounder were well-predicted by theory, the existence of spurious responses or ‘self-noise’ was an ongoing concern. Many authors offered explanations for why such self-noise was occurring and suggestions for how it could be suppressed. We attempted to verify the authors’ conclusions by replicating their setups and conducting experiments, but were unsuccessful.

Our conclusion: Reviewers and editors had done science a disservice by forcing authors to idly and incorrectly speculate concerning the causes of observed behaviour. Once reported in the literature, and cited by authors who were in turn cited by other authors, myths die hard. Moreover, none of these authors seemed to be aware of similar work being conducted by the acoustics community which was often more sophisticated than those employed by wireless researchers. The published literature concerning suppression of self-noise in stepping correlator channel sounders is a cautionary tale that reveals how a process designed to ensure that truth is fully revealed can actually do just the opposite.

Reading Galvanometers: Infrastructure and Instrumental Practice of Electrical Metrology at the University of Toronto
Author: Chen-Pang Yeang; Erich Weidenhammer; Victoria Fisher; Ava Spurr; Patrick Finnigan

Historians of science and technology have explored scientific instruments for their implications to metrology, the concepts of precision, materiality of laboratories, pedagogy, and tacit knowledge. We use the galvanometers as a lens to study the local development of expertise and training in electrical science and technology. Galvanometers were known for their precision in measuring minute electric currents. Integral to industry and science from the mid-19th to the 20th century, these instruments gained prominence as fundamental tools in electrical metrology. Their significance and operational challenges required specialized training in physics and electrical engineering.
In this paper, we inspect a set of historical galvanometers and the teaching of their uses at the University of Toronto. We adopt two materially-oriented methodologies. The first, informed by the Winterthur method of “artifact reading,” examines four historical galvanometers from the University of Toronto Scientific Instruments Collection to trace the development of local metrology and its broader Canadian context. The second, guided by experimental replication and a close reading of curricula and students’ lab notebooks from the University of Toronto Archives, aims to reconstruct the pedagogical practice and embodied skills involving galvanometers. Our study showcases the fruitfulness of materially-engaged methodologies in investigating the laboratory practice, teaching, and material conditions surrounding a ubiquitous measuring instrument at a Canadian university in the 20th century.

Co-author bio notes:
Chen-Pang Yeang is an Associate Professor at the Institute for the History and Philosophy of Science and Technology, University of Toronto.