ACADEMY OF SCIENCES. 



219 



Regular Meeting, April 15th, 1872. 

 Vice-President in the Chair. 



Twenty-four members present. 



James S. Hutchinson and William S. Watson were elected resi- 

 dent members. 



Donations to the Museum : Skin of an albatross and head of a 

 wild-cat, by John Williamson. Specimens of Metacinnabarite, by 

 Henry Carlton. 



Prof. Whitney made some remarks on a mass of meteoric iron, 

 which is in the possession of Mr. Cronise, the weight of which is 

 about ninety pounds. He explained on the map the region where 

 these meteorites have been found, showing them to occur in a line 

 from Mexico to Oregon ; specimens of meteoric iron of gigantic 

 size had been reported from Port Orford, but recent search by the 

 U. S. Coast Survey had failed to reveal any in that locality. 



Mr. Durand presented the following paper : 



Notes on the Crystallization of Metacinnabarite. 



BY F. E. DURAND. 



The specimens of Metacinnabarite. formerly found, were too imperfect to 

 allow any determination of the crystalline form ; but lately some very good 

 specimens have been received, and it is now possible to determine their form. 



Figs. 1 and 2 show the form of the 

 crystal — although the new specimens 

 contain remarkable crystals. The 

 study of this mineral is d'fiRcult ; the 

 large crystals being an agglomeration 

 of smaller ones. 



But the consideration of Fig. 2 

 shows that this mineral crystallizes in 

 the orthorhombic system. 



The planes A, B, C, are the prim- 

 ary planes of the rectangular prism, 

 and E, G, H, I, eight modifying planes 

 irregularly placed on the eight triedral 

 angles of the prism, the equation of the 

 modifying planes will be, a : mb : nc. 



Fig. 1. 



