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QUANIA / Biography gallery

İZ Lives That Left a Mark

How did the world change after one decision?

An experiment, a calculation or a letter. This gallery begins with a person’s choice and follows it into the lives of others.

Reading index
Symbolic light drawing
Explore the 3D light model

Illuminated plates on two levels form the gallery’s opening composition.

The room’s still light drawing is above.

Biography gallery

Memory here lives in documents, stories and institutions carried across generations. Each dossier considers the person’s role alongside collaborators and the communities who lived with the consequences.

011971–1972

China · Medicine and experiment

Tu Youyou

A text changes an experimental condition

Before the decision

Chinese teams searching for new antimalarial drugs screened many plant extracts. While studying Artemisia annua, Tu Youyou’s team returned to the preparation method in a historical recipe by Ge Hong.

Open the deeper reading

Turning point

The recipe suggested avoiding high heat. The team tested extraction at lower temperatures. After obtaining an active extract, researchers isolated artemisinin. Reading the old text had brought a testable variable into view.

Effects and costs

Artemisinin and its derivatives became important in malaria treatment through development and clinical research by multiple teams. Tu’s contribution offers a concrete example of how a historical text can inform experimental work.

How to read the evidence

The Nobel lecture is Tu’s retrospective account. The scientific review separates testing an extract from identifying the purified compound.

Sources

  • Tu Youyou · Nobel Lecture
  • Nobel Assembly · Scientific background
  • Youyou Tu · Nature Medicine, 2011, author’s account
    Where to look
    Tu Youyou’s 2011 article, first page, Figure 1 and the accompanying account of the experiment
    Reading clue
    Figure 1 shows a printed version of the recipe transmitted by Ge Hong. Tu links her reading of it to the idea that high temperatures might have damaged the active constituent. Distinguish the clue in the recipe from the team’s experiment at lower temperature.
    What the source can establish
    The article is a researcher’s retrospective account. The recipe itself cannot establish clinical efficacy. Testing an extract and identifying the pure compound are separate results.
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021977–2004

Kenya · Environment and civic life

Wangari Maathai

Whose work is it to plant a tree?

Before the decision

Kenyan biologist Wangari Maathai began with problems rural women faced in securing firewood, water and food. Loss of soil and woodland was making daily work harder.

Open the deeper reading

Turning point

Beginning in 1977, the Green Belt Movement organised seedling nurseries and tree planting with local women’s groups. As knowledge and responsibility moved into the hands of people who worked with the land each day, a project grew into a wider movement.

Effects and costs

The movement made visible the link between protecting the environment and participating in public decisions. Maathai received the 2004 Nobel Peace Prize. The work behind it included many people raising seedlings and protecting land.

How to read the evidence

An award documents the founder’s role. Assessing local impact also calls for the records and testimony of different communities.

Sources

  • Wangari Maathai · Nobel biographical account
  • Nobel Committee · 2004 Peace Prize
  • Green Belt Movement · History
    Where to look
    Green Belt Movement history, the founding in 1977 and local nurseries
    Reading clue
    Read the opening on drying streams and the growing difficulty of finding firewood, then follow the account of women collecting seeds and raising seedlings. The sequence shows the everyday problems that came before any planting target.
    What the source can establish
    The history records how the movement explains its own development. Local records and participant testimony are needed to assess economic or environmental effects in a particular village.
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031691

New Spain, present-day Mexico · Literature and education

Sor Juana Inés de la Cruz

A letter opens a reading room

Before the decision

The poet and nun Sor Juana wrote in New Spain, where women’s access to advanced learning was limited. The bishop of Puebla had her critique of a theological text published and addressed advice to her under the name Sor Filotea.

Open the deeper reading

Turning point

In her reply of 1691, Sor Juana recounted how she learned. She drew on her own experience and on written authorities to defend women’s education. The form of a personal letter carried a public question about who could produce knowledge.

Effects and costs

The letter offers a way to examine education, religious authority and authorship in the colonial period through one document. It gives readers access to Sor Juana’s own voice alongside the accounts of later biographers.

How to read the evidence

The document is a reply and a defence. Read the conditions it describes alongside the rhetorical choices its author made to persuade her reader.

Sources

  • UNAM · Carta a Sor Filotea, catálogo
    Where to look
    UNAM SIBILA, catalogue record 201, subject heading and publication details
    Reading clue
    The subject heading dates the letter to 1691. The publication details place this version in a journal printed in Bogotá in 1951. The two dates on the same screen separate the writing of the text from its republication centuries later.
    What the source can establish
    The catalogue helps trace circulation. To read Sor Juana’s defence, turn to the letter’s text or a facsimile.
  • Secretaría de Cultura de México · Edición facsimilar
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0415th century BCE

Ancient Egypt · Trade and representation

Hatshepsut

When a voyage is carved into stone

Before the decision

Hatshepsut ruled as pharaoh in the Eighteenth Dynasty and had the expedition to Punt depicted at her temple at Deir el-Bahari. The carved scenes show ships, encounters and goods brought to Egypt.

Open the deeper reading

Turning point

The account includes myrrh trees, making visible both the ritual and commercial importance of distant travel. Sailors, local counterparts and people who moved the cargo made the expedition possible.

Effects and costs

The temple shows how a ruler turned a voyage into state memory. The same relief gives us only an indirect view of the people of Punt.

How to read the evidence

The reliefs present a royal account. They cannot by themselves establish Punt’s exact location or the full conditions of exchange.

Sources

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0511th century

Basra and Cairo · Optics

Ibn al-Haytham

How does light reach the eye?

Before the decision

In the Book of Optics, Ibn al-Haytham treated the propagation of light, the structure of the eye and perception together. His account of vision starts with light reaching the eye.

Open the deeper reading

Turning point

He used observation and experiment alongside geometry to describe the relation between points in the field of view and the eye. The work also asks under what conditions an account of sight can be tested.

Effects and costs

The text shaped the history of optics through Arabic manuscripts and circulation in other languages. Translators and later readers helped carry its influence.

How to read the evidence

The manuscript catalogue traces a document. Sabra’s translation allows its concepts to be read. Crediting a single figure with all modern optical methods would obscure that complex transmission.

Sources

  • Wellcome Collection · A. I. Sabra’s edition of the Optics, books I–III
  • British Library · Ibn al-Haytham, manuscript catalogue
    Where to look
    British Library, IO Islamic 461, folios 8v–34r, treatise on the solar eclipse
    Reading clue
    The record points to the opening lines about light passing through a small aperture onto an opposing surface, and to the foldout at 34r that holds four diagrams. The manuscript approaches a question about light through both text and figures.
    What the source can establish
    This is a separate treatise on eclipses. For the account of vision in Books I–III of the Book of Optics, follow the dossier’s link to Sabra’s translation.
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06Early 11th century

Heian Japan · Literature and the court

Murasaki Shikibu

Reading a court from within

Before the decision

Murasaki Shikibu served at the Japanese court in the early eleventh century. The Tale of Genji brought the jealousy, vulnerability and loneliness behind ceremonies and family relations into an expansive narrative.

Open the deeper reading

Turning point

The work shows how courtly order looks from different social positions. Genji has considerable room to act, while rank and reputation constrain the decisions of women in the story.

Effects and costs

Readers and artists reinterpreted the text over centuries in illustrated scrolls, manuscripts and printed books. Its reach is visible in those literary and visual traditions as well as in the writing itself.

How to read the evidence

The digitised edition is evidence of later circulation. Fictional scenes raise questions about court life. They cannot by themselves supply the evidence of a historical record.

Sources

  • The Met · The Tale of Genji exhibition
    Where to look
    The Met exhibition, Tosa Mitsuoki’s portrait-icon of Murasaki Shikibu
    Reading clue
    Compare the seventeenth-century date in the image caption with the eleventh-century setting in the introduction. Painted on silk centuries later, the image shows how later artists represented Murasaki.
    What the source can establish
    The image cannot serve as an eyewitness portrait. It bears witness to the author and the work as they were remembered later.
  • Library of Congress · The Tale of Genji, digitised edition
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071852

United States · Abolition and public speech

Frederick Douglass

Answering a celebration with a question

Before the decision

Frederick Douglass, a writer and speaker who had escaped slavery, addressed an Independence Day gathering in Rochester on 5 July 1852. An abolitionist organisation had invited the audience to assemble.

Open the deeper reading

Turning point

Douglass placed the ideal of independence beside the lives of people excluded from it. A national commemoration became a public test of claims about citizenship and freedom.

Effects and costs

Publication carried the address beyond the hall. Within the long struggle to end slavery, the text shows how political language can be held to its own stated principles.

How to read the evidence

Print preserves words. It does not record every listener’s response or measure what the speech changed by itself.

Sources

  • Library of Congress · Frederick Douglass’ Paper, 9 July 1852
    Where to look
    Frederick Douglass’ Paper, 9 July 1852, page 2, Corinthian Hall coverage
    Reading clue
    The newspaper first reports on the event and then prints the speech. Compare the opening recognition of the struggle for independence with the passages in which Douglass places himself apart from the celebration. The question gains force through that turn.
    What the source can establish
    The issue preserves the speech in print. It cannot reproduce the speaker’s voice, his pauses or every listener’s reaction.
  • Library of Congress · The 1852 address and its context
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081938–1939

Austria, Germany and Sweden · Nuclear physics

Lise Meitner

From chemical evidence to physical explanation

Before the decision

Otto Hahn and Fritz Straßmann found chemical evidence for barium after bombarding uranium with neutrons. Lise Meitner, who fled Germany in 1938 because she was Jewish, continued to correspond from Sweden.

Open the deeper reading

Turning point

Meitner and Otto Frisch developed an explanation in which a heavy nucleus divides into lighter fragments. Their 1939 paper also considered the energy released in the process.

Effects and costs

This path in nuclear physics later intersected with energy and weapons technologies. The initial chemical observation, its physical interpretation and subsequent applications involved different people and decisions.

How to read the evidence

The paper records a particular physical explanation. How credit was distributed and how later technologies were used require separate evidence.

Sources

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091960–1962

United States · Orbital mathematics

Katherine Johnson

Calculating an orbit a second time

Before the decision

A 1960 NASA technical note by Katherine Johnson and Ted Skopinski describes how to determine a launch direction so that a satellite passes over a chosen position on Earth.

Open the deeper reading

Turning point

NASA records that Johnson verified the electronic computer calculations for John Glenn’s 1962 orbital flight. A person and a machine were parts of a common task with a check between them.

Effects and costs

The work shows that spaceflight depends on mathematics, coordination and verification alongside a spacecraft and its pilot. The signed technical report also makes a mathematician’s contribution visible.

How to read the evidence

The 1960 note documents a particular mathematical problem. NASA’s institutional account describes the assignment for Glenn’s flight. They concern distinct pieces of work.

Sources

  • NASA Technical Note D-233 · Skopinski and Johnson, 1960
    Where to look
    NASA Technical Note D-233, third PDF page, summary and introduction
    Reading clue
    The report looks for the heading at the end of powered flight that will bring a satellite over a chosen place after several orbits. The authors begin with a rotating spherical Earth and then account for the difference made by its flattening. Follow those two steps separately.
    What the source can establish
    The calculation concerns passing over a selected location. Johnson’s separate verification assignment for Glenn’s flight is documented elsewhere.
  • NASA · Katherine Johnson at Work, 1962
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101964

South Africa · Apartheid and political rights

Nelson Mandela

Arguing for equal citizenship in court

Before the decision

Under apartheid, Nelson Mandela and other defendants faced sabotage charges in the Rivonia Trial. Mandela made a statement from the dock on 20 April 1964.

Open the deeper reading

Turning point

He defended the opposition’s turn to sabotage and set out a vision of a society based on equal political rights. Two months later Mandela and seven other defendants received life sentences.

Effects and costs

The statement became part of the international memory of opposition to apartheid. The end of the system came through a much longer process involving many organisations, strikes, international pressure and negotiations.

How to read the evidence

The text is a historical defence by a defendant. Court records and the testimony of other participants in the movement provide additional points of view.

Sources

  • Nelson Mandela Foundation · Rivonia statement, transcript
    Where to look
    Rivonia statement, the passage in which Mandela lists four methods the movement considered
    Reading clue
    Mandela links his account of why sabotage was chosen to the future of political relations. Read that passage alongside the closing description of a society based on equal rights.
    What the source can establish
    The statement shows how a defendant justified the decision. It does not independently verify every action of the organisation or its effects.
  • Nelson Mandela Foundation · Rivonia sentencing
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The Work Behind the Invention

An experiment, a calculation, a material or a manufacturing method may come long before the device we know. This collection traces those steps and the people who took them through the documents they left.

Explore HEURISKA’s invention archive
111315

Artuqid court · Clocks and mechanisms

Al-Jazari

Making elapsed time visible

Before the decision

Al-Jazari recorded water clocks and other mechanisms in drawings and construction instructions.

Open the deeper reading

Turning point

In the elephant clock, an interval measured with water is translated into a sequence of visible and audible actions every half hour.

Effects and costs

The design treats measurement, triggering and a visible signal as parts of one mechanism.

How to read the evidence

The folio on display dates from 1315 and belongs to a copy made after the author’s lifetime.

Sources

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121856

United States · Gases and heat

Eunice Newton Foote

Comparing warming in two cylinders

Before the decision

Foote used glass cylinders and thermometers to compare the warming of different gases in sunlight.

Open the deeper reading

Turning point

In 1856 she reported greater warming and slower cooling in the cylinder containing carbon dioxide.

Effects and costs

The simple apparatus made the relation between atmospheric composition and temperature a question that could be investigated.

How to read the evidence

Temperature differences in a glass vessel do not account for all radiative processes in the atmosphere.

Sources

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131882

United States · Lighting manufacture

Lewis Howard Latimer

Protecting a thin carbon strip

Before the decision

Keeping a delicate conductor intact during manufacture was a problem in its own right for carbon-filament lamps.

Open the deeper reading

Turning point

In 1882 Latimer patented a carbonising process that enclosed strips in protective envelopes during heating.

Effects and costs

The work makes visible the manufacturing and materials knowledge behind the spread of electric lighting.

How to read the evidence

The document is a patent for a particular carbonising process.

Sources

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141899 / 1902

United Kingdom · Electric arcs

Hertha Marks Ayrton

Listening to an unsteady light

Before the decision

Arc lamps produced light through an electrical discharge between carbon electrodes. Hissing and flicker were practical problems.

Open the deeper reading

Turning point

Ayrton investigated the electrode tips and oxygen’s access to the carbon to explain conditions under which the arc became unstable.

Effects and costs

The research connected what people saw in street and stage lighting to the behaviour of the electrodes.

How to read the evidence

The dossier concerns historical experiments with the open carbon arc.

Sources

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151912

United States · Astronomy and measurement

Henrietta Swan Leavitt

From a star’s rhythm to distance

Before the decision

Leavitt compared the brightness of variable stars in the Small Magellanic Cloud on photographic plates.

Open the deeper reading

Turning point

The 1912 study of 25 stars showed that the brighter variables had longer periods.

Effects and costs

Once calibrated, the relation became one step in measuring cosmic distances.

How to read the evidence

The stars compared were treated as being at roughly the same distance. An absolute scale required other measurements.

Sources

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161904

Bengal · Wave detectors

Jagadish Chandra Bose

What changes at a contact when a signal arrives?

Before the decision

Bose investigated electrical responses at contacts between solid materials to detect electromagnetic waves.

Open the deeper reading

Turning point

His 1904 US patent described sensitive materials including galena and a detector with adjustable contact force.

Effects and costs

Turning a weak disturbance into an electrical response made receiver design a subject of research in its own right.

How to read the evidence

The patent documents a detector design. It cannot account for the whole history of wireless communication.

Sources

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171948

Hungary and United States · Solar heat and storage

Mária Telkes

Carrying the day’s heat into the night

Before the decision

Telkes developed a way to store solar heat for later use through a salt’s change of phase.

Open the deeper reading

Turning point

The system was tested in an occupied home at the 1948 Dover Sun House, designed by Eleanor Raymond with support from Amelia Peabody.

Effects and costs

The experiment showed that storing heat and distributing it efficiently through a home were distinct engineering problems.

How to read the evidence

Fan electricity and component failures limited the expected savings in the experimental house.

Sources

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181954

India and United Kingdom · Fibre optics

Narinder Singh Kapany

Carrying an image around a bend

Before the decision

Kapany and Harold Hopkins developed a flexible imaging device using a bundle of light-guiding fibres.

Open the deeper reading

Turning point

The approach reported in 1954 preserves the relative order of fibre ends so that parts of an image can be assembled at the far end.

Effects and costs

Carrying an image along a bendable path was an important step for flexible imaging instruments.

How to read the evidence

An imaging bundle represents one branch of development in fibre optics. Modern communications networks use additional technologies.

Sources

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191959 / 1962

Sweden · Vehicle safety

Nils Bohlin

Two paths meet at one buckle

Before the decision

Bohlin designed the anchorage and operation of a belt that crossed the chest and hips of a seated occupant.

Open the deeper reading

Turning point

In the design used by Volvo in 1959, the chest and lap sections formed one continuous belt fastened at their junction.

Effects and costs

Thinking about anchorage and ease of use together helped a safety device become a routine part of driving.

How to read the evidence

The US patent granted in 1962 concerns the particular arrangement described in the document.

Sources

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201956–1957

China and United States · Experimental physics

Chien-Shiung Wu

Measuring a mirror symmetry

Before the decision

Wu worked with colleagues at the National Bureau of Standards to test whether a weak interaction behaved like its mirror image.

Open the deeper reading

Turning point

They measured an asymmetry in the directions of beta electrons emitted by oriented cobalt-60 nuclei.

Effects and costs

The result provided experimental evidence that parity is violated in a weak interaction.

How to read the evidence

The result concerns a particular process. Other interactions require their own tests.

Sources

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211960s / 1974

United States · Polymers and fibres

Stephanie Kwolek

Testing a solution by spinning it

Before the decision

At DuPont, Kwolek worked on making fibres from rigid-chain aromatic polymers.

Open the deeper reading

Turning point

An unusual solution produced strong fibres when spun. Testing and scale-up helped turn the laboratory result into a usable material.

Effects and costs

This work contributed to the development of Kevlar fibre. Spinning, testing and production teams played distinct roles.

How to read the evidence

Fibre properties and the protective performance of a finished product require different tests.

Sources

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221980s

United States · Satellite geodesy

Gladys West

Positioning begins with measuring Earth

Before the decision

West worked on processing satellite data and modelling the shape of Earth.

Open the deeper reading

Turning point

Her GEOSAT work included processing radar altimeter measurements. Co-authored technical records show the contribution in its team setting.

Effects and costs

Positioning accuracy also depends on measurements and reference models for Earth. That infrastructure is easy to overlook when using a receiver.

How to read the evidence

This dossier covers West’s contribution to satellite geodesy. A positioning system’s hardware and protocols have a broader history.

Sources

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231891

Germany · Surface physics

Agnes Pockels

Compressing a film on water

Before the decision

Pockels used a trough with a movable divider to investigate how a thin film behaved at the surface of water.

Open the deeper reading

Turning point

Sliding the divider changed the area available to the film while she measured surface tension. She described her experiments in a letter published in Nature in 1891.

Effects and costs

Controlling the available surface area made it possible to compare the behaviour of very thin films spread on water.

How to read the evidence

The apparatus measures surface behaviour. Identifying the molecules in a film requires other methods.

Sources

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241942

Mexico · Television and colour

Guillermo González Camarena

Showing the same colour at the same instant

Before the decision

González Camarena designed an arrangement that captured and displayed colour components in sequence.

Open the deeper reading

Turning point

In the US patent granted in 1942, red, green and blue filter discs turn together at the transmitter and receiver. The corresponding filter must arrive in time for the picture.

Effects and costs

The arrangement exposes a practical part of colour reproduction. After separating the colour information, the receiver must show it at the right moment.

How to read the evidence

The patent concerns one particular arrangement for sequential colour.

Sources

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251950

Argentina · Biochemistry and sugars

Luis Federico Leloir

Finding a missing participant in a reaction

Before the decision

Leloir and his colleagues investigated how cells convert certain sugars into one another.

Open the deeper reading

Turning point

In 1950, Caputto, Leloir, Cardini and Paladini reported that they had isolated UDP-glucose from yeast. It acts as a coenzyme in the conversion of galactose phosphate to glucose phosphate.

Effects and costs

Research on nucleotide sugars helped explain how cells add sugar units to larger structures.

How to read the evidence

One paper identifies a participant in one conversion. Other studies established later biosynthetic pathways.

Sources

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261959–1960

Egypt, Korea and the United States · Semiconductors

Mohamed M. Atalla and Dawon Kahng

Making the silicon surface controllable

Before the decision

A transistor gate uses an electric field to control current. Electronic states at the silicon surface made that control difficult.

Open the deeper reading

Turning point

Atalla and his Bell Labs colleagues studied how an oxide layer grown with heat could stabilise the silicon surface. Atalla and Kahng took that work into a transistor with a metal gate, insulating oxide and silicon. The device was demonstrated in 1960.

Effects and costs

That work on the surface helped later teams put many MOS transistors on a single chip.

How to read the evidence

The early device demonstrated that a gate could control current in this structure. The speed and production scale of later chips are documented separately.

Sources

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271986

Japan · Crystal growth and light

Hiroshi Amano and Isamu Akasaki

The thin layer that came before blue light

Before the decision

When gallium nitride was grown on sapphire, the mismatch between their crystal structures could impair the quality of the film.

Open the deeper reading

Turning point

The 1986 paper by Amano, Sawaki, Akasaki and Toyoda described growing a higher-quality film by placing a thin aluminium nitride buffer between sapphire and gallium nitride.

Effects and costs

To build a light-emitting device, researchers first needed a crystal of sufficient quality. This approach addressed one of the materials problems on the way to blue LEDs.

How to read the evidence

The paper concerns crystal film growth. An efficient blue LED required further work on the electrical properties of the semiconductor and on the device itself.

Sources

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281971

Uruguay and the United States · Materials and controlled release

Alejandro Zaffaroni

Making the release rate part of the design

Before the decision

How to store an active substance and how quickly to let it leave its reservoir are two separate design questions.

Open the deeper reading

Turning point

In Zaffaroni’s patent granted in 1971, a layered patch holds the substance in a central reservoir. The material in the reservoir wall is chosen to limit the rate of release.

Effects and costs

The design gave concrete form to an idea. A material property could control how release proceeded over time.

How to read the evidence

The patent describes a design. Studies of an individual product establish its safety and effectiveness.

Sources

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291977

India · Solar radiation

Anna Mani

Measuring the same sun from different stations

Before the decision

Solar radiation at ground level depends on a station’s altitude and on the conditions the light encounters as it passes through the atmosphere.

Open the deeper reading

Turning point

In 1977, Mani, O. Chacko and V. Desikan compared observations from the Himalayas and elsewhere in India. Before the monsoon, stations in Kashmir recorded less direct solar radiation than Kodaikanal despite low humidity. The team pointed to the effect of fine particles suspended in the air.

Effects and costs

Separating direct radiation from radiation scattered in the atmosphere helps explain differences between stations. The measurement handbook Mani compiled places such work in a wider body of data.

How to read the evidence

The paper compares particular stations and observation periods. The researchers inferred the effect of airborne particles from the pattern of measurements.

Sources

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301963–1964

South Africa and the United States · Cross-sectional imaging

Allan M. Cormack

Reconstructing a slice from many beam paths

Before the decision

As a beam passes through an object, it weakens along its path. One reading tells us how much it weakened in total, while the location of that loss remains unknown.

Open the deeper reading

Turning point

Cormack asked how measurements along different paths could reveal the distribution inside a cross-section. His papers of 1963 and 1964 developed methods for that calculation.

Effects and costs

The work became one of the mathematical foundations for reconstructing a slice from external measurements. Godfrey Hounsfield developed a scanner through a separate engineering effort in the same field.

How to read the evidence

The early papers study reconstruction under specific assumptions. Hospital scanners also required hardware development and clinical evaluation.

Sources

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311962

Spain · Tools for reading and learning

Ángela Ruiz Robles

Changing lessons inside a single book

Before the decision

Ruiz Robles, a teacher, designed a device that would let a pupil read material on several subjects using the same apparatus.

Open the deeper reading

Turning point

In the 1962 patent, text and illustrations sit on a flexible strip running between two spools. Turning a spool brings the next passage to a reading window. A museum collection preserves the prototype made in Ferrol.

Effects and costs

Separating the reading surface from the lesson material meant the same device could serve several subjects. That exchangeable content was central to the educational design.

How to read the evidence

The patent explains the intended operation and the museum documents a built prototype. Widespread classroom use is a separate historical question.

Sources

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321962–1965

United States and Germany · Acoustics

James E. West and Gerhard M. Sessler

A thin film that moves with sound

Before the decision

In a condenser microphone, sound moves a thin diaphragm. Its movement changes the capacitance between two surfaces, and that change becomes an electrical audio signal.

Open the deeper reading

Turning point

West and Sessler used a thin material that could retain its electrical polarisation for a long time. Their 1965 study describes how the approach eliminated external polarising voltage in the capsule and compares how different film materials behaved over time.

Effects and costs

The film itself supplied one of the electrical conditions required to capture sound. That simplified the design of the capsule.

How to read the evidence

Polarising voltage for the capsule and power for the microphone circuitry serve different purposes. The measurements concern the films and devices studied.

Sources

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331903

United States · Transport and visibility

Mary Anderson

Clearing the glass from inside

Before the decision

When rain or snow stuck to the front window, the driver needed a way to restore visibility while the vehicle was moving.

Open the deeper reading

Turning point

In Anderson’s 1903 patent, a handle inside the vehicle moves the cleaner on the outside of the window through an arc. A flexible support keeps the cleaner in contact with the glass.

Effects and costs

The design aimed to make clearing the window an action a driver could perform from inside the vehicle, even while moving.

How to read the evidence

The patent describes one hand-operated mechanism. Motorised wipers and mass production are documented separately.

Sources

  • Mary Anderson · US743801A, Window-cleaning device
    Where to look
    US743801A, description of the interior handle and claims 3–4
    Reading clue
    Identify the handle inside and the cleaner outside. Then see how the mechanism maintains contact and what path the cleaner follows on the glass.
    What the source can establish
    The patent documents the movement and parts. The museum account places the arrangement in the wider history of streetcar and automobile use.
  • National Inventors Hall of Fame · Mary Anderson
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