Significant figures: caesium-137.

One in an ongoing monthly series published in Chemistry World, the RSC's member magazine. Each illustration surrounds a portrait of a chemist — often a woman whose contributions were overlooked — with an ornamental frame specific to her work. Here, the chemical notation ¹³⁷Cs appears in the upper left corner, integrated into the vine and leaf border. The frame is not decoration; it is a document, holding the scientific life of a person written out of history. The constraint remains constant across the series — black and white, ornamental, portrait-centred — yet each commission opens a different archive. The work requires patience to read slowly: the hidden notation, the compound folded into ornament, the diagram that doubles as vine.