Compound interest was known to ancient civilisations, but as far as we know it was not until medieval times that mathematicians started to analyse it in order to show how invested sums could mount up and how much should be paid for annuities. Starting with Fibonacci in 1202 A.D., techniques were developed which could produce accurate solutions to practical problems but involved a great deal of laborious arithmetic. Compound interest tables could simplify the work but few have come down to us from that period. Soon after 1500, the availability of printed books enabled knowledge of the mathematical techniques to spread, and legal restrictions on charging interest were relaxed. Later that century, two mathematicians, Trenchant and Stevin, published compound interest tables for the first time. In 1613, Witt published more tables and demonstrated how they could be used to solve many practical problems quite easily. Towards the end of the 17th century, interest calculations were combined with age-dependent survival rates to evaluate life annuities, and actuarial science was created.

John Locke's comparison of the mind to a blank piece of paper, the tabula rasa, was one of the most recognizable metaphors of the British Enlightenment. Though scholars embrace its impact on the arts, humanities, natural sciences, and social sciences, they seldom consider why the metaphor was so successful. Concentrating on the notebooks made and used by the schoolchildren of Enlightenment Scotland, this essay contends that the answer lies in the material and visual conditions that gave rise to the metaphor's usage. By the time students had finished school, they had learned to conceptualize the pages, the script, and the figures of their notebooks as indispensable learning tools that could be manipulated by scores of adaptable folding, writing, and drawing techniques. In this article, I reveal that historicizing the epistemology and manipulability of student manuscript culture makes it possible to see that the success of Locke's metaphor was founded on its appeal to everyday note-keeping activities performed by British schoolchildren.

Visual inscriptions (e.g., graphs, illustrations) are a defining feature of scientific discovery to aid in data analysis, interpretation, and communication (e.g., Latour, 1990; Lynch, 1985). Our purpose was to examine how visual inscriptions are used to present data in gerontology journals. We compared 357 articles sampled from 24 peer-reviewed gerontology journals published between 1995 and 2009. Approximately 11 per cent of page space was dedicated to data presentation with more page space occupied by tables (9.13%) than graphs (2.32%). Graph use in gerontology was lower than in psychology (6.6% of page space) and higher than in criminology and criminal justice (1.7% of page space). Following Latour (1990), we argue that visualisations provide an understandable summary of complex data by effectively presenting multifaceted results. When inscriptions are used in dissemination, researchers become less reliant on complex statistical jargon and can communicate easily with a diverse audience (researchers, health care practitioners, clients).