MEMOIR XX.] TIIK ALLOTROPISM OF CHLOHIM! 



In offering these experiments and arguments to the 

 consideration of chemists, I am fully aware of the mag- 

 nitude of the change which would be impressed on the 

 science generally, and especially on several modern theo- 

 ries, by their reception. The long -established idea of 

 the immutability of the properties of elementary bodies 

 would, to a certain extent, be sacrificed ; and it is prob- 

 able that before these results are conceded more cogent 

 evidence of the main principle will be required. In the 

 meantime, however, it is plain that the admission of 

 these doctrines throws much light on theories now ex- 

 tensively attracting attention, and for that reason they 

 commend themselves to our consideration. I have of- 

 fered no opinion here on the atomic mechanism involved 

 in these changes from an active to a passive state, 

 though it is impossible to deal with these things with- 

 out the reflection arising in our minds that here we are 

 on the brink of an extensive system of evidence con- 

 nected with the polarity of atoms an idea which, under 

 a variety of forms, is now occurring in every department 

 of natural philosophy. 



UNIVERSITY OF NEW YORK, July 29, 1845. 



