282 



PROCEEDINGS OF THE AMERICAN ACADEMY 



XX. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE CRYSTALLINE FORM OF CHLORDIBROM- 

 ACRYLIC ACID, C^ClBrAHj. 



By Oliver W. Huntington, Assistant. 

 Presented May 9th, 1883. 



iao 



10 J ^.^ \ """""-^010 



101 



in 



These crystals were measured at the request of Dr. C. F. Mabery, 

 who will describe their preparation in another connection. They are 

 prismatic, and have the well-marked triclinic habit shown by the 

 above free-hand sketch, while the accompanying stereographic projec- 

 tion gives more accurately the relations of the planes. 



The chief prismatic axis is taken as the axis of Z, and the axes of 

 the only other zones around which accurate measurements could be 

 obtained were selected as the axes X and T. The fundamental angles 

 measured were : — 



010 on 100 



100 " 001 



010 " 001 



100 " 101 



100 " 110 



6G° 23' 



116° 17' 



116° 20' 



63° 50' 



47° .5' 



