@rosalind_franklin

Rosalind Franklin

I am a chemist and X-ray crystallographer. My research science reveals the molecular structures of DNA, RNA, viruses, coal and graphite from the patterns X-rays leave on film.

Proof · case studies

Cases

The situation, the work, the outcome. Ranked by how much the work proves.

I reconciled my DNA data into two helices

1952 — 1953

Situation

Through 1952 Raymond Gosling and I worked through the X-ray pictures of DNA; three draft manuscripts followed in early 1953.

Action

By January 1953 I had reconciled conflicting diffraction data and concluded that both DNA forms had two helices. My A-DNA manuscripts reached Acta Crystallographica on 6 March 1953, before I knew of the Cambridge model.

Outcome

Patient research on the data reached a double-helical backbone independently of the model builders.

dnax-ray crystallographydouble helix

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I separated DNA into its A and B forms

1951 — 1951

Situation

John Randall redirected me to DNA fibres in 1951; I was the only experienced experimental diffraction researcher at King's, working with the graduate student Raymond Gosling.

Action

I built a humidity-controlled camera chamber at King's College London and used it to show that DNA exists in two forms, which I named A and B — a result that reshaped the research on the molecule.

Outcome

Controlling one physical variable — humidity — turned a blurred science problem into two clean, separable structures.

x-ray crystallographydnaexperimental design

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How I photographed DNA fibres at set humidity

1951 — 1952

My method for getting usable X-ray diffraction images of DNA fibres: a refined fine-focus tube and microcamera, a humidity-controlled chamber, then Patterson analysis of the pictures.

x-ray crystallographyinstrumentationexperimental design

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I won Birkbeck's largest grant to study polio

1956 — 1957

Situation

Colleagues at Berkeley suggested polio in 1956; the work needed live virus, safely stored at the London School of Hygiene and Tropical Medicine.

Action

I won £10,000 over three years from the US National Institutes of Health — the largest fund Birkbeck had ever received — and began determining the crystal structure of the polio virus.

Outcome

I could move my structural research from plant to animal viruses and fund it at an unprecedented scale.

virologyresearch fundingx-ray crystallography

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I proved every tobacco mosaic virus is the same length

1954 — 1956

Situation

From 1954 I led an Agricultural Research Council group at Birkbeck College with Aaron Klug, John Finch, Kenneth Holmes and Donald Caspar.

Action

At Birkbeck I used X-ray crystallography on tobacco mosaic virus and showed in Nature (1955) that all its particles are the same length — against the eminent virologist Norman Pirie — then led the research on its structure.

Outcome

Leading a small research group, I turned structural science from DNA to RNA viruses and was proved right.

x-ray crystallographyvirologyrna

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I measured the holes in coal with helium

1942 — 1945

Situation

From 1942 I fulfilled National Service as an assistant research officer at BCURA, in wartime Britain.

Action

At the British Coal Utilisation Research Association I studied coal porosity using helium to measure density, linking pore constrictions to permeability. The research became my 1945 Cambridge PhD.

Outcome

Fundamental science on pore structure let industry classify coals and predict their fuel and gas-mask performance.

physical chemistrycoalporosity

Open card

Proof · case studies

Cases

The situation, the work, the outcome. Ranked by how much the work proves.

I reconciled my DNA data into two helices

1952 — 1953

Situation

Through 1952 Raymond Gosling and I worked through the X-ray pictures of DNA; three draft manuscripts followed in early 1953.

Action

Outcome

Patient research on the data reached a double-helical backbone independently of the model builders.

dnax-ray crystallographydouble helix

Open card

I separated DNA into its A and B forms

1951 — 1951

Situation

John Randall redirected me to DNA fibres in 1951; I was the only experienced experimental diffraction researcher at King's, working with the graduate student Raymond Gosling.

Action

I built a humidity-controlled camera chamber at King's College London and used it to show that DNA exists in two forms, which I named A and B — a result that reshaped the research on the molecule.

Outcome

Controlling one physical variable — humidity — turned a blurred science problem into two clean, separable structures.

x-ray crystallographydnaexperimental design

Open card

How I photographed DNA fibres at set humidity

1951 — 1952

My method for getting usable X-ray diffraction images of DNA fibres: a refined fine-focus tube and microcamera, a humidity-controlled chamber, then Patterson analysis of the pictures.

x-ray crystallographyinstrumentationexperimental design

Open card

I won Birkbeck's largest grant to study polio

1956 — 1957

Situation

Colleagues at Berkeley suggested polio in 1956; the work needed live virus, safely stored at the London School of Hygiene and Tropical Medicine.

Action

I won £10,000 over three years from the US National Institutes of Health — the largest fund Birkbeck had ever received — and began determining the crystal structure of the polio virus.

Outcome

I could move my structural research from plant to animal viruses and fund it at an unprecedented scale.

virologyresearch fundingx-ray crystallography

Open card

I proved every tobacco mosaic virus is the same length

1954 — 1956

Situation

From 1954 I led an Agricultural Research Council group at Birkbeck College with Aaron Klug, John Finch, Kenneth Holmes and Donald Caspar.

Action

Outcome

Leading a small research group, I turned structural science from DNA to RNA viruses and was proved right.

x-ray crystallographyvirologyrna

Open card

I measured the holes in coal with helium

1942 — 1945

Situation

From 1942 I fulfilled National Service as an assistant research officer at BCURA, in wartime Britain.

Action

At the British Coal Utilisation Research Association I studied coal porosity using helium to measure density, linking pore constrictions to permeability. The research became my 1945 Cambridge PhD.

Outcome

Fundamental science on pore structure let industry classify coals and predict their fuel and gas-mask performance.

physical chemistrycoalporosity

Open card