Memorizing numerical data in the 17th and 18th centuries. Technical innovations and new practices

Because the classical art of memory was part of rhetoric, Latin authors did not develop detailed techniques for memorizing numbers. During the Renaissance, some methods for memorizing numerical data were added to the ars memoriae, partly due to the growing readership of memory treatises among merchants. However, the memorization of numerical data remained a marginal topic in memory manuals, and the available techniques were cumbersome when dealing with multiple long numbers. As numerical thinking became prevalent in the “outillage mental” of the time, a specific mnemonic technique was devised in the 17th century. By converting numbers into consonants and then forming words by adding vowels, mnemonists could employ mental images to represent these words and effectively memorize the corresponding numbers. This paper aims to trace the spread of this new technique from France to the Holy Roman Empire and, in the 18th century, to England. Additionally, it will show how new fields of knowledge were incorporated into treatises of the 17th and 18th centuries. Thus, this paper will shed light on how the Scientific Revolution led to the development of new mnemonics by practitioners with sociological backgrounds different from those of Renaissance humanists and orators.