Christian Gottfried Ehrenberg (1795-1876) is renowned for pioneering work on microscopic organisms. His fame is based mainly on his two beautifully illustrated monographic works. The first was the 1838 monograph on living microorganisms ’Infusoria’ with 64 plates, and the second in 1854, Mikrogeologie with 41 plates showing the remains of microorganisms in minerals and sedimentary deposits. Largely due to these two major works, Ehrenberg is recognized as a founder of protistology on one hand and micropaleontology on the other. The illustrations in Ehrenberg’s two monographs are well known but they represent less than half the plates contained in his works and many of Ehrenberg’s publications did not concern microorganisms, living or fossil. Here are shown the lesser-known scientific illustrations, revealing the surprisingly wide range of his scientific investigations and consequently his artwork. Following a biographical sketch of Ehrenberg’s life, to place in perspective his works, a selection of these scientific illustrations are presented. The illustrations are drawn from his articles and pamphlets published from 1818 to 1859. Later publications all concerned protists, and contain illustrations thought to be likely the work of his daughter Clara who acted as his essential aide when he became physically diminished in old age.
The influence of the neoplatonic Academy of Florence on the work of Leonardo da Vinci is shown. His fascination for the sacred geometry, the flower of life and especially the golden number appears in many Leonardo’s drawings and paintings. We also show that several sages of the Antiquity are portrayed as apostles in the Last Supper testifying that Leonardo was very interested in the culture of the neoplatonic Academy in search of a syncretism between Plato’s philosophy and Christianism. Finally, we show that the Vitruvian man is designed on the basis of two golden rectangles exactly like the ideal horse probably drawn at about the same time. (Cf. Arts et Sciences n°6, 2022, 48-54).
A recently discovered drawing of a horse by Leonardo da Vinci gives us the opportunity to highlight the ubiquitous use of the golden ratio by the master, confirming the Greek inspiration of who was nicknamed the “new Phidias”. The horse drawn by Leonardo can be seen as an “ideal horse”, with perfect measurements for the body as well as the head, according to the “divine proportion”, i.e. the golden ratio. This also allows us to point out a very good approximation and simple geometric construction of the golden ratio.
From the end of the 19th century onwards, a renewed approach to the spectator’s perceptive act in the theoretical discourse on art was asserted, concomitantly with the psychological and philosophical discourse. The spectator’s act of perception would explain certain pictorial illusions. Beyond that, the perceptive act could play a new role in the apprehension of a colour or a quality of texture, linking it, by association or equivalence, to other sensations, tactile, olfactory, sonorous, just as immediately perceived by going beyond the naturalistic principles of imitation. In this paper, I will first highlight the evolution of one of the theories of art focusing on the notion of suggestion, then to show how different non-figurative propositions after the Second World War are in line with the continuity of this conception through a creative research on how to make perceptible on a flat surface an impression of depth, expanse, or swirls; a matter or a form perceived as sharp or rough, not trying to depict either the object or a sensation but to create an "equivalence that determines a sensation" (P. Tal Coat). In parallel with a revival of psychology, considering that our perception establishes relationships in the visual field, that we grasp structures significant to all the senses, many artists started a creative research on how to make visible sensations anchored in their experience of the sensitive world, which for them often give rise to others, emotional or spiritual, inducing a feeling "beyond words and intellectual frameworks" (D. Vallier). The singular nature of this aesthetic, which maintains an unexpected link with reality, provokes a debate on its attachment to abstract art.
The relationship between the mineral and the living has always been a subject of debate, but nowadays it is of growing interest, probably due to scientific advances that have blurred the classical distinction between living and non-living. The first part of this article explores various passages from mineral to living: in ancient stories (Genesis and Greco-Roman mythology) and contemporary role-playing games on the one hand, and in the emergence of life on the other, as understood by science over the centuries. The second part focuses on the reverse passages, from the living to the mineral: several possible mineralizations of organisms, in vivo (biomineralizations) and post mortem (fossilizations, petrifications), with their artistic and literary revivals, are thus addressed. The third part evokes the proximities between the mineral and the living: natural proximities (in particular those involving epiliths such as lichens) or due to humans (from prehistoric cave paintings to Arte povera). We will finally see how certain writers and artists reach a true intimacy with the mineral world in which they project themselves and find themselves.
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