After Warburg's death in October 1929 and the migration of the Institute to London in 1933, Brunian studies at the Warburg Institute took a very different direction thanks to the research of Frances Yates (1899-1981). While Warburg's interest in Bruno and image-based thinking brought his philosophy towards the present, Frances Yates' hypothesis of an Hermetic Bruno rooted his thought in a distant and partly mythical past at the antipodes of modern times. Nevertheless, while her Giordano Bruno and the Hermetic Tradition (1964) takes a different path from that traced by Warburg, her other Brunian study, The Art of Memory (1966), is perhaps her book closest to Warburg's preoccupations. Indeed the history of mnemonics practices, by means of which mythological figures lived from the Antiquity onwards as animated bearers of learning in the intimacy of the human brain, had everything to interest Warburg. In fact the Art of Memory was written in close consultation with Gertud Bing as confirmed by this excerpt from the preface:Now that the Memory Book is at last ended, the memory of the late Gertrud Bing seems more poignantly present than ever. In the early days, she read and discussed my drafts, watching constantly over my progress, or lack of progress, encouraging and discouraging by turns, ever stimulating with her intense interest and vigilant criticism. She felt that the problems of the mental image, of the activation of images, of the grasp of reality through images – problems ever present in the history of the Art of Memory – were close to those which preoccupied Aby Warburg, whom I only knew through her.Frances Yates expounded the first results of her research on Bruno's art of memory in a seminar at the Warburg Institute in 1952. She showed her reconstruction of the wheel described in the De Umbris Idearum, Bruno’s first mnemonic work published in Paris in 1582. The two wheels illustrated below are part of the same work and serve as an introduction to using the larger wheel.
In the first fixed ring the practitioner will assign a mythological or heroic figure to each letter. Bruno provides some examples : A Lycaon; B Deucalion; C Apollo; D Argos ... (see De Umbris Idearum, pp. 107 ff). The letters of the second ring correspond to an action or a scene associated with each figure. The examples provided are: AA Lycaon at a banquet; BB Deucalion and pebbles; CC Apollo and Python; DD Argos and some cattle (ibid, p. 112). Thus rotating the first inner ring operates permutations between the figures and their action. Further permutation occurs when the third wheel is set in motion. It contains attributes or enseignes which can be easily passed from one figure to another. Bruno provides only four examples and leaves the rest to the imagination of his reader. These are : AAA, Lycaon at a banquet with a chain; BBB, Deucalion and pebbles with a headband; CCC, Apollo and Python with a baldric; DDD, Argos and some cattle with a hood. This way the systems makes it possible to create combinations of letters representing words, acronyms or syllables to be remembered by means of animated images mixing the attributes and accustomed actions of familiar mythological figures.
BAA: B Deucalion A at a banquet A with a chain
MAD: M Perseus A at a banquet D with a hood
CAD: C Apollo A at a banquet D with a hood
COD: C Apollo O and Proserpina D with a hood
To approach the larger wheel Bruno advises his reader that `...it is necessary to dilute the printed page into an immense space'. The last section of De Umbris idearum describes the content of the larger wheel over 40 pages. It consists of five concentric rings divided into 150 rays each subdivided in 5 cells. On the outer rings are numbers, letters, the name of inventors followed by four more wheels of words corresponding to the categories of agent, action, enseignes, attributes (adstans) and circumstance.
`How did the system work? By magic of course, by being based on the central power station of the … images of the stars, closer to reality than the images of things of the sublunar world, transmitter of the astral forces, the `shadows’ intermediary between the ideal world above the stars and the objects and events in the lower world.’ (The Art of Memory, p. 223)This interpretation, based on a misplacing of the images of the planets, was first revised by Rita Sturlese in her critical edition of the De Umbris of 1991 (pp. LXVIII ff.) and later by Francesco Torchia (‘La chiave delle ombre’, Intersezioni, 1, 1997, pp. 131-151).
Both scholars strip Bruno’s construction of its magical character. According to Sturlese the wheel is in fact an adult toy conceived to learn foreign words. Here each ray corresponds to a set of syllables combining one consonant with one vowel. Thus reconstructing a word with its phonetic constituents amounts to combining the various elements of each section. The addition of the images described in the last ring before the hub creates in the end a mnemonic background by means of which new words can be remembered. For instance to remember the word Numeratore you should pick the first syllable in the outer ring, NU, which corresponds to `Apis’; the second syllable in the second ring, ME: `in tapeta ’; the third syllable, RA, in the third ring: `deploratus’; the fourth syllable, TO, from the 4th ring: `compedes’; and finally RE in the 5th ring. This last ring provides a background against which to set the image thus created: `…mulier super hydram tres cervices e quarum singulis septem exiliunt capita habentem, vacuas antrorsum tendens manus’ (De Umbris, p. 151).