The Eighteenth Century 165 



the french encyclopedie 



The great French Encyclopedie of the eighteenth century origi- 

 nated in a French translation (1745) of Ephraim Chambers' Cyclo- 

 pedia. However, a much more ambitious compilation was soon 

 planned which, over a period of years, passed through a remarkable 

 history of delay and censorship. It finally appeared as thirty-nine 

 huge volumes in 1777-1779 under the editorship of Denis Diderot 

 (1712-1784) and Jean Baptiste le Rond D'Alembert (1717-1783), 

 both eminent scholars and scientists. In this work, entitled Encyclo- 

 pedie, ou Dictionnaire raisonne des Sciences, des Arts et des Metiers, 

 par un Societe de Gens de Lettres,^^ luminescences are mostly con- 

 sidered under the heading " Phosphore," although the article " Feu 

 electrique " by M. le Monnier is comprehensive, describing the 

 electroluminescence observed by von Guericke, Boyle, Dufay, Hauks- 

 bee, and others. The article on " Lumiere " merely mentions the 

 light of phosphors, diamonds, and feu electrique. 



Although the basis of the Encyclopedie was Ephraim Chambers' 

 compilation, it is difficult to recognize this origin for the article, 

 " Phosphore." The idea that luminescence and electricity are closely 

 related is the main theme of the presentation. The existence of 

 phlogiston is also assumed, for the text had been completed before 

 Lavoisier's discoveries. Phosphores are divided into six categories: 

 (1) Animal bodies " which the electric fluid has penetrated and 

 rendered luminous," such as the glowworm, the lucciole, insects of 

 the Canals of Venice, flies of the Antilles, the tong^ue of the irritated 

 viper, eyes of some living animals, the flesh of those recently killed, 

 certain fish, some shellfish, the coats and hair of many animals when 

 rubbed vigorously. " These bodies are not all organized to exhibit 

 the electric phosphorescence constantly, as the electric torpedo or 

 electric eel, but they become so under certain circumstances during 

 love, irritability and anger, among many others. The identity of 

 the nervous fluid and the electric fluid is well known." (2) Inani- 

 mate electric phosphores, excited by friction such as the globe of 

 Hauxbee. (3) A group of substances rendered luminous by brisk 

 striking or friction which electrifies or puts into movement their 

 innate light or inflames the phlogiston which they contain. Such 

 are sugar, diamonds, or quartz pebbles. (4) The solar phosphori 

 that must be first exposed to light in order to shine. (5) Phosphores 

 produced by putrid fermentations, distillation of inflammable sub- 



^' The Encyclopedie methoclique of the bookseller, C. J. Panckoucke, started appear- 

 ing in 1781 and was not complete in 1832, after 166 volumes had appeared. One part, 

 the Dictionnaire de physique (1793) contains an excellent article on " L'aurore boreale.' 



