26 PROCEEDINGS OF THE AMERICAN ACADEMY. 



10. The molecular weight of one of the green substances is probably 

 large. 



11. All these experiments agree in pointing toward the existence of a 

 green basic salt in which at least 47 per cent of the acid radical is re- 

 placed by hydroxyl. It is possible that there may be several compounds' 

 of different degrees of hydrolysis. The acid set free seems to be sul- 

 phuric acid, and not a complex acid. It is unsafe at present to apply 

 any definite formula to the basic salt. Further investigation will be in- 

 stituted in order to discover if possible its structure, as well as to deter- 

 mine whether or not a colloidal substance also exists in the hydrolyzed 

 solution. 



A Chronological Bibliography of the Change in Chromic 

 Salts from Violet to Green. 



By Frederic Bonnet, Jr. 

 1828. Fischer, G. 



Zur nahern Kenntnis der Chromsalze. Kastner's Archiv. f. Naturlehre, 

 14, 164. 

 1838. Rose, H. 



Ueber das Chlorchrom. Pogg. Ann., 45, 183. 



1841. Schrotter, A. 



Ueber die Schwefelsaure-chromoxydsalze. Pogg. Ann., 53, 513. 



1842. Hertwig, C. 



Ueber die in Wasser schwerloslichen und unaufloslichen Modificationen 

 des schwefelsauren Kali-chromoxyd. Pogg. Ann., 56, 95. 



1843. Peligot, E. 



Ueber das Chromsesquichloriir. C R., 21, 74-81. 



1844. Kopp, E. 



Note sur le sulfate chromique. C. R-. 18, 1156-58. 

 1844. Kriiger. 



Ueber die Farbenveranderung, welche das neutral Schwefelsaure-chro- 

 moxyd in der Auflosung in Wasser durch Erhitzen bis zum Kochpunkt 

 erleidet. Pogg. Ann., 61, 218. 



1844. Berzelius, J. J. 



Ueber die Allotropie einfacher Korper, als eine der Ursachen zur lsomerie 

 ihrer Verbindungen. Pogg. Ann., 61, 1. 



1845. Loewel, H. 



Ueber das Chromoxyd u. seine isomern Modificationen. Jl. de Pharm. et 

 Chim. [3], 4 Ann., 321-344, 401-424; Centralbl., 1845, p. 561. 

 1845. Pelouze, J. 



Note sur le sesquichlorure de chrome. Ann. de Chim. et Phys. [3], 14, 

 247; Chem. Centralblatt, 1845, S. 603. 



