Early 18th-century developments in optics led to the invention of this type of microscope in order to observe “animalcules”, a term defined as follows in the Encyclopédie: “This word usually designates animals so small that they can only be seen through a microscope. Since the invention of this instrument, we have seen small animals we never knew before […]”.The microscope helped to prove theories on the development of life in microbial cultures. Diderot referred to these experiments in his reflections on deism and materialism. He was influenced by the English biologist John Needham (1713–1781), who defended the theory, published in 1745, of the spontaneous generation of microscopic life. In his 1749 Lettre sur les aveugles à l’usage de ceux qui voient, Diderot questioned the existence of God based on Needham’s observations.

This painting is a second version of an eponymous composition presented by Gabriel François Doyen at the Salon du Louvre in 1759. It is the “piece” that the artist presented for his reception at the Académie royale de peinture et de sculpture on 23 August 1759. Denis Diderot saw the painting when he visited the Salon in 1759, but did not write about it. The Académie played a major role in Parisian artistic life. Exhibitions of its members’ recent works were held every two years in the Louvre’s Salon carré.

The plaque inside the lid of the box indicates that the chronometer was made by “James Hatton, CHRONOMETER MAKER to the Hon(oura)ble the EAST INDIA COMPANY, St Michaels Alley, Cornhill, LONDON”. The dial bears the manufacturer’s signature and the item’s serial number (400).

The marine chronometer was a significant18^th-century breakthrough because it made precise timekeeping possible on long sea voyages. In combination with a sextant, the chronometer allowed seafarers to calculate a ship’s longitude, which they could not do before. The marine chronometer was invented and gradually perfected by the English watchmaker John Harrison (1693–1776) between 1736 and 1759. Chronometers were commonly used on ships between 1770 and 1780. The use of chronometers at sea became widespread in the 1770s.

A true portrait of Ancien Régime society, this scene depicts a Normandy Lord, the Seigneur de Canon, Jean-Baptiste Élie de Beaumont (1732–1786), and his wife Anne-Louise, ceremonially awarding deserving peasants – the eponymous “good people” – prizes for their upstanding character and morals. At the centre of the painting, a virtuous maiden is crowned with roses; at her side is a wise old man waiting to receive a crown of oak leaves and ears of wheat. Gifts also await them: bags of coins, medals, clothes and a blue ribbon worn by the Count of Artois as a sign of protection. This ceremony actually took place in Canon in 1775, and was followed by a party. Such events pointed to the new relationship that enlightened aristocrats sometimes hoped to establish with the Third Estate, under the auspices of the clergy. Such charitable performances nevertheless also affirmed the pre-eminence of the aristocracy in the social hierarchy.

This work, presented in 1777 at the Salon de l’Académie royale de peinture et de sculpture, is characteristic of the period’s taste for paintings with edifying moral messages, in contrast with the frivolity of earlier subjects. Pierre-Alexandre Wille trained under the great artist Jean-Baptiste Greuze (1725–1805). Like Greuze, he painted virtuous themes (almsgiving, filial duty, the patriarchal family, village harmony, morality, etc.). Although Denis Diderot never saw this particular painting, he knew the organisers of the ceremony and supported their initiatives. He also approved of paintings on such subjects, because he felt that art could serve a useful moral purpose and improve minds.

This painting probably belonged to the Marquis de Clermont d’Amboise (1728–1792), French ambassador to Naples between 1776 and 1782. It is representative of the work of the French painter Pierre Jacques Volaire, who specialised in views of Vesuvius. After working with the landscape painter Joseph Vernet, he moved to Rome in 1762, then Naples in 1767. Shifting away from the seascapes associated with his master, he focused on depictions of Vesuvius, whose eruptions he witnessed in 1767, 1771, 1779 and 1794. The painting represents a spectacular eruption that took place between 8 and 15 August 1779. The explosions lit up the sky as Vesuvius spewed out an impressive volume of volcanic matter, including lava plumes that shot up into the air and flowed down its slopes, and clouds of volcanic ash. These eruptions attracted scientists and curious visitors from all over Europe. The fashion for paintings of Vesuvius was tied to the rise of the veduta, a new genre of landscapes sold as souvenirs to predominantly English and French sightseers on their Grand Tour to Italy.

This work illustrates the evolution of taste in Diderot’s day, notably the period’s predilection, notably among art-loves, for the “sublime spectacle” of awe-inspiring natural landscapes. Diderot discusses this new taste in his writings on poetry and the arts. In the article “Beau” in the Encyclopédie, he distinguishes between the sublime and beauty: “It seems that in our language the idea of beautiful is always associated with that of greatness […]”. Yet “the idea of great , sublime , elevated , has no place on those occasions when one still uses the word beautiful. Just survey in this way all the beings that are called beautiful : one will exclude greatness; […] some even the marked appearance of order and symmetry; such would be the painting of a storm, a tempest, chaos”.