156 History of Luminescence 



were published in the memoirs of the French Academy of Sciences 

 in 1726, 1732, and 1738. He is perhaps best known for his interest 

 in electricity, but he also wrote on chemistry and many other sci- 

 ences. In 1732 Dufay was appointed Director of the Jardin des 

 Plantes in Paris, but despite this contact with living things, he made 

 no real study of bioluminescences and never collected his researches 

 on inorganic luminescences into a book. This was no doubt due to 

 the fact that Dufay's death occurred when he was only forty-one 

 years old, thus cutting off a brilliant career. His ideas, as expressed 

 in his published papers, will be found in Chapters VH, VIII, and 

 IX, devoted to electroluminescence, phosphorescence, and thermo- 

 luminescence, respectively. 



Another eminent Frenchman of independent means, Rene An- 

 toine Ferchault de Reaumur (1683-1757) , admitted to the Academy 

 in 1708, is best known for studies in the mechanical arts (conver- 

 sion of iron to steel, 1722) , as a physicist (introduction of a par- 

 ticular thermometer scale, 1731) , and as an entomologist {Memoires 

 pour Servir a I'Histoire des Insectes, 6 v., Paris, 1734-1742) . How- 

 ever, his interest in luminescence is attested by the monograph on 

 the light of the mollusc, Pholas, dactylus, Des MerveiUes des Dails 

 (1723) . This work was apparently inspired by the hope of pre- 

 serving indefinitely the luminous secretion of the mollusc. Although 

 no liquid preservative was found, Reaumur did notice that dried 

 Pholas would again light when moistened. He thus gave the first 

 proof that water was necessary for bioluminescence, a finding not 

 tested on other luminous forms until the work of Spallanzani on 

 medusae in 1794. Reaumur's experiments are described in Chapter 

 XVI. 



It is unfortunate that Reaumur did not complete the history of 

 insects. The volume on beetles remained unfinished. Had he 

 studied the glowworm with the care he lavished on the silkworm, 

 science would have had the first accurate knowledge of its life his- 

 tory, habits, and fine structure. This gap was to be filled by Baron 

 Carl De Geer (1720-1778) of Stockholm, in 1755, and by the French- 

 man, Philibert Gueneau de Montbeillard (1720-1785) , in 1782. 



Beccari and the Bolognian Institute 



In Italy a group of workers, chief of whom was Jacopo Bartolomeo 

 Beccari (1682-1766) , carried out experiments on luminescent ma- 

 terials, both organic and inorganic, and published a series of papers 

 (1731-1747) in the Commentarii de Bononensi, official organ of the 

 Bologna Institute of the Sciences and Arts, founded by Count Mar- 

 sigli in 1711. Soon after the foundation, Beccari was appointed pro- 



