Source / Statistical diagram
Florence Nightingale's celebrated 1858 diagram arranged monthly British Army death rates in coloured sectors, making mortality from preventable disease visually overwhelm deaths from wounds.
Its force came from design and argument together: carefully selected categories, comparable rates, explanatory text, colour, and circulation turned administrative data into a case for sanitary reform.
Reading the source
Each equal-angle sector represents one month. Coloured areas within it separate deaths from preventable or mitigable disease, wounds, and all other causes, while the two circles compare successive years.
Reading from the centre outward can be deceptive because viewers often compare radii instead of areas. The graphic's geometry makes large mortality differences visually forceful, but it demands careful attention to its explanatory key. Nightingale was not decorating a table: she was choosing a form in which magnitude, cause, sequence, and reform could be grasped together.
The diagram represents deaths in relation to the strength of the army and expresses them as annual rates. It is therefore not a simple count of bodies, even though its expanding sectors create an immediate impression of scale.
Blue-grey areas for disease dominate much of the first year, while red marks wounds and black other causes. The dramatic contraction after sanitary changes presents preventable mortality as an administrative problem open to action.
Placed together, the periods before and after the Sanitary Commission's arrival invite comparison over time. The graphic condenses extensive tables into a form intended to hold the attention of officials and reformers.
Construction and limits
Cause-of-death categories, army strength, dates, rates, colours, scale, and layout are interpretive choices. Reading the diagram historically means asking how military records were produced and how uncertain diagnoses became stable statistical groups.
The familiar labels “coxcomb” and “rose diagram” can blur distinctions among Nightingale's several graphics. This source is more precisely a polar-area diagram, and its design drew on a wider culture of vital statistics rather than appearing without precedent.
Nightingale directed the analysis and used graphics strategically, but the source also depended on clerks, medical officers, printers, collaborators, soldiers, and statisticians including William Farr. Their records and labour sit behind the finished plate.
Across the collection
Follow Nightingale's nursing, statistical, administrative, and reform work beyond the familiar Crimea narrative.
Place the graphic within mortality counting, comparison, standardisation, trials, risk, and evidence.
Connect statistical and sanitary advocacy to the later institutional organisation of nurse education.