OF ARTS AND SCIENCES. 77 



Weight of Antimonious Bromide taken . . 32.2938 grammes. 

 Specific gi'avity referred to Kerosene at 23° . 5.386 

 „ „ Water at 23° . 4.148 



By the same methods used with antimonious chloride, we made 

 several determinations of both the melting and the boiling points of 

 purified antimonious bromide, with the following results : — 



Melting point of Antimonious Bromide . 93^^ C. 

 Boiling point „ „ . 280° C. 



Antimonious Iodide (Sbig). 



There are three crystalline conditions of antimonious iodide, — the 

 hexagonal, the orthorhombic, and the clinorhombic or monoclinic, of 

 which only the first has hitherto been described. 



Hexagonal Antimonious Iodide. 



Hexagonal crystals of iodide of antimony of a deep ruby red color 

 can be readily obtained, either by cooling or by evaporating a satu- 

 rated solution of this substance in disulphide of carbon, and this 

 solution is easily prepared (as described in the previous paper) by 

 shaking up, with finely pulverized metallic antimony until the color is 

 discharged, a strong solution of iodine in the same solvent. These 

 crystals were described by Nickles, in connection with those of antimo- 

 nious bromide, in the paper just referred to. He states that they are 

 hexagonal, double pyramids, with a basal angle of 133° ; and his de- 

 scription is referred to by Schneider,* who also obtained hexagonal 

 crystals, both from the disulphide of carbon solution, and also by sub- 

 liming a mixture of antimonious sulphide with iodine. Schneider 

 speaks of the crystals as brilliant, sharp, six-sided leaves or tables ; but 

 gives no additional measurements. All the crystals which we have 

 examined (and we have seen the products of a great number of crystalli- 

 zations) are combinations of a rhombohedron with its first obtuse rhom- 

 bohedron and the basal planes, as shown in Figs. 4 and 5, Plate I. The 

 habit of the crystals, however, differs very greatly with the conditions 

 under which they are formed. When deposited during the rapid cool- 

 ing of a solution saturated at the boiling point of the very volatile sol- 

 vent, they are, as Schneider states, small and leaf-like, with a very 

 definite hexagonal outline ; but still, when seen with a microscope by 



* Poggendorff, Annalen, cix. 610, 1860. 



