212 History of Luminescence 



A number of other apparent chemiluminescences of inorganic 

 material have been reported— from mixing lime and water, observed 

 in the eighteenth century; also a light on new-cut surfaces of the 

 metal potassium, reported by W. Petrie in 1850. The potassium 

 luminescence in air is presumably analogous to that of phosphorus, 

 although little studied. Many types of luminescence in flames were 

 reported in the nineteenth century and a consideration of some of 

 these will be found in Chapter XIII. 



The nineteenth century is chiefly notable for the first instance 

 of a similar light emitting reaction in solution from a known or- 

 ganic chemical, which was actually demonstrated in the laboratory. 

 The discovery was made by Bronislaus Radziszewski (born 1838), 

 professor of chemistry at Lemberg (Galicia) . He found that com- 

 pounds containing the triphenylglyoxaline ring, such as amarin and 

 lophin, would, when dissolved in alcohol and shaken with air in 

 alkaline solution, oxidize with light emission. 



The observation was published in 1877, over two hundred years 

 after the discovery of phosphorus. It was followed in 1880 with a 

 list of many additional organic compounds which were also chemi- 

 luminescent and Radziszewski himself pointed out the importance 

 of the find for the explanation of bioluminescences. Later workers 

 soon added more compounds to the list, but Radziszewski may be 

 credited with founding the science of chemiluminescence in solu- 

 tion. Luminescence of phosphorus takes place in the vapor phase. 

 A more detailed history of the subject is related in Chapter XIII on 

 chemiluminescence. 



EARLY TEXTBOOKS OF CHEMISTRY AND PHYSICS 



It is not possible to discuss luminescence as expounded in the 

 various textbooks of chemistry and physics, or in the encyclopedias 

 of the nineteenth century, in any detail. They usually gave excel- 

 lent accounts under various headings and the treatment by some 

 authors was outstanding. The subject was very much in the public 

 eye and a few representative texts will be mentioned. The views 

 of Brugnatelli, who wrote a two-volume text, Elementi di Chimica 

 in 1795-1797, and of Davy, whose Elements of Chemical Philosophy 

 appeared in 1812, have already been quoted. 



Another popular chemistry, that of William Henry (1799) , was 

 brought out in an American edition (1808) , sponsored by John 

 Maclean, professor of natural philosophy and chemistry in the Col- 

 lege of New Jersey (later Princeton University) and by Benjamin 

 Silliman, professor of chemistry in Yale College, New Haven, Conn., 



