PREFACE. ix 



nected with phosphoric phenomena, or the spon- 

 taneous emission of light by natural or artificial 

 substances, as well as by living and dead organic 

 bodies, these phenomena must be studied in the 

 whole domain of Nature in the mineral, in the 

 vegetable, and in the animal world. I have there- 

 fore brought forward what I know on the subject, 

 with regard to mineral substances, and have ex- 

 tended my investigations to vegetables, to animals, 

 and to organic matter deprived of life. The phe- 

 nomenon of Phosphorescence will thus have been 

 studied simultaneously throughout Nature, and 

 this is, to my knowledge, the first time that the 

 interesting series of facts I have consigned to 

 these pages have been looked upon as constitu- 

 ting a whole. 



Phosphorescent properties, although developed 

 to a prodigious degree in the insect world, are 

 found nevertheless to exist in numerous other ani- 

 mals, in many plants, and also in certain minerals 

 and chemical products. They pertain at once to 

 the science of chemistry and physics, as well as to 

 botany and physiology. Those who possess a 

 profound knowledge of these different branches of 

 natural history, can alone hope to arrive at the 



