404 CHEMICAL FORCE IN THE SPECTRUM. [MEMOIR XXIX. 



MEMOIR XXIX. 



ON THE DISTRIBUTION OF CHEMICAL FORCE IN THE 

 SPECTRUM. 



From the American Journal of Science and Arts for December, 1872, and January, 

 1873; Philosophical Magazine, December, 1872. 



CONTENTS: The curves of the calorific, luminous, and chemical spec- 

 tra. Their errors. Inappropriateness of the term actinic rays. 

 There is no localization of chemical effects. Every radiation can pro- 

 duce some specific effect. Case of the silver compounds. Bitumens 

 and resins. Carbonic acid. Colors of flowers. Law of Grotthus 

 Chlorine and hydrogen. Bending of stems of plants. Absorption es- 

 sential to chemical action. Decomposition of silver iodide. Union of 

 chlorine and hydrogen. Angstrom's law. General conclusions. 

 Chemical force exists in every portion of the spectrum. Each radia* 

 tion exercises chemical influences proper to itself. 



WITH scarcely an exception, the most recent works on 

 the chemical action of radiations and spectrum analysis 

 describe a tripartite arrangement of the spectrum, illus- 

 trated by an engraving of three curves, exhibiting the 

 supposed relations of the calorific, the luminous, and the 

 chemical spectra. This view, which by a mass of evi- 

 dence may be shown to be erroneous, is exerting a very 

 prejudicial effect on the progress of actino-cheniistry. 



I propose now to present certain facts which may aid 

 in correcting this error. For this purpose it is necessary 

 to show that chemical effects decompositions and com- 

 binations may take place in any part of the spectrum. 

 The points to be established may be thus distinctly 

 stated : 



1st. That so far from chemical influences being re- 



