OP ARTS AND SCIENCES. 75- 



meanwhile with the bulb of the thermometer, which was immersed up 

 to the division on the stem marking 15^, The prejiaration used in this 

 determination was that "designated by f, in the table on page 40 ; and 

 we obtained, as the 



Melting point of Antimonious Chloride, 11° C. 

 We obtained also, and in the usual way, for the 



Boiling point of Antimonious Chloride, 216'^ C. 



In several instances, while rectifying this substance as described in the 

 last paper, we followed the boiling point, and observed that it was con- 

 stant, during the whole period of the distillation. 



Antimonious Bkomide (SbBrg). 



The methods used for preparing and purifying the bromide, as well 

 as the chloride, of antimony, have been so fully described in the previ- 

 ous paper that no further details are necessary here. We obtained 

 very brilliant crystals of the bromide, not only by the two methods 

 described under the last head, but also by sublimation with the appa- 

 ratus represented on page 57 of this volume. As treated in either of 

 these ways, the habit of the substance is to form needle-shaped crys- 

 tals, which run out into fine points without definite terminations, and 

 often group themselves into irregular bundles, — a very common feat- 

 ure of this type of crystals. Only on one occasion (then by slowly 

 cooling a solution in disulphide of carbon) did we obtain well termi- 

 nated crystals ; and, although we afterwards tried again and again, we 

 have not yet been able to reproduce them. Unfortunately, moreover, 

 before we were ready to make our measurements, the small terminal 

 planes of these crystals had already become tarnished by the atmos- 

 phere. For, although the substance is so much less hygroscopic than 

 antimonious chloride, yet the crystals of antimonious bromide soon 

 lose their sharpness, if exposed even to what we call our dry wiuter 

 air. Hence, we were not able to measure the angles between the 

 terminal planes with a reflective goniometer. The approximate value 

 of 101 on 100, we obtained by measuring the corresponding edge 

 angle under the microscope, and by frequent repetitions of the measure- 

 ment on different crystals, or on the two sides of the same crystal, 

 securing as great accuracy as is possible under such circumstances ; but 

 the result cannot be relied upon within one or two degrees. 



