The Nineteenth Century 203 



existed, but was not material in the sense that terrestrial bodies 

 were material. He thought that the " light substance " and " heat 

 substance " were different. 



The sections on the " Phosphoren " were particularly full, giving 

 an excellent resume of the important work on light-absorbing phos- 

 phors, luminous wood and flesh, luminous animals, the sea, light 

 from rubbing, heating, etc. Here is to be found the beginning of 

 Heinrich's interest in luminescence phenomena which was to lead 

 him to compete for another prize offered by the French Academy, 

 and finally to the publication of his great work, Die Phosphorescenz 

 der Korper, in 1811-1820. 



In 1807, the French National Institute, Class of Mathematical 

 and Physical Sciences, offered a prize of 3,000 francs, to be adjudged 

 at the meeting on the first Monday in January, 1809, for the follow- 

 ing subject: " To establish, by experiments, what are the relations 

 which exist between the different modes of phosphorescence, and 

 to what cause is each owing; excluding the examination of the phoe- 

 nomena of this kind observed in living animals." The prize was 

 instigated by Abbe Rene Just Haiiy (1743-1822) , the famous pro- 

 fessor of mineralogy at the Museum d'Histoire Naturelle and honor- 

 ary canon of Notre-Dame, whose Trait e de Miner alogie (1801) 

 contained a list of thermoluminescent minerals. The memoirs had 

 to be delivered to the Academy before October 1, 1808. Anyone 

 not a member of the Institute might be a candidate and like the 

 St. Petersburgh prizes, the essays had to bear only a sentence, with 

 the author's name in a sealed note. 



Among others, Placidus Heinrich (1758-1825) and a Frenchman, 

 Jean-Philibert Dessaignes, submitted essays and Dessaignes won the 

 prize. ^ However, Heinrich was too much interested in the subject 

 to be deterred by this disappointment. He collected his experiments 

 and notes, which were published as the first large work on all types 

 of luminescence to appear in the nineteenth century, a huge collec- 

 tion of miscellaneous knowledge. The book, Die Phosphorescenz 

 der Korper, was a real monograph of 596 pages (see title page in 

 fig. 19) . It is divided into five sections, appearing separately be- 

 tween 1811 and 1820. They represent the ideas of that day on the 

 classification of luminescences and it is interesting to note that all 

 the bioluminescences were grouped together in the third section 

 (1815) entitled, " Vom Leuchten vegetabilischer und thierischer 



^Another contemporary student of luminescence, Theodor von Grotthuss (1785- 

 1822) , did not compete for a prize. His papers are considered in Chapters VIII and 

 IX. David Brewster (1781-1868) also worked on luminescence during the same period 

 (see Chapter IX and XI) . 



