4 Dr. E. J. Mills's Researches on Melting-point 



benzol (permanently reddened by bromine) for a short time 

 nearly to boiling, washing and rectifying the product. The 

 benzol thus purified was used in preparing benzol by Couper's 

 process*; and from this product, on distillation, a residue of 

 dibromobenzol was obtained. This was crystallized once from 

 spirit, twice from naphtha, and thrice from spirit ; at the last 

 crystallization the substance was only partly dissolved ; and the 

 crystals obtained from the solution were alone examined. 

 C was prepared from the monobromobeazol above referred to. 

 The product of Couper's process always contains a little dibro- 

 mobenzol, which cannot be removed in the ordinary way. 

 This was allowed to remain. Traces of another solid impurity 

 were precipitated by exposure to sunlight for some weeks in 

 presence of solid potassic hydrate, followed by filtration and 

 distillation. Finally the purified monobromobenzol was mixed 

 with bromine in the proportion C 6 H 5 Br : Br 2 , and left for 

 some weeks in the laboratory, during which it was once heated 

 in the water-bath. The product was washed with aqueous 

 caustic soda, some unaltered monobromobenzol removed by 

 partial distillation with water, and the remainder crystallized 

 once from alcohol, once from naphtha, and once from alcohol 

 in presence of charcoal (Ci): successive fractions (C 2 &c) 

 from alcohol were then taken. G§ a was obtained from a hot 

 liquid which had deposited about half its contents, which I 

 have named G^. 



Dibromobenzol melts nearly as sharply as dichloroberjzol. 

 It is hardly possible to trace a pasty stage. 



Table III. 





A. 



A. C, 



c- 



3 . 



C 4 . 



c 8 . 



tw 



C 6/3- 





87-08 







8705 87-10 



86-97 



87-06 



87-10 



8704 



87-06 







c 



87-10 





87-03 



87-07 86-99 



87-08 



8701 



87-05 



87-01 



87-06 



87-05 





86-87 



87-03 87-12 



86-97 



87-03 



87-10 



87-01 



87-03 



86-94 





86-97 



87-05 86-99 



87-16 



8703 



87-10 



8701 



86-98 



8707 





87-00 



87-01 87-10 



87-13 



87-11 



87-05 



8701 



87-09 



87-07 





86-97 



86-96 87 07 



86-99 



87-01 



87-07 



87-01 



87-06 



8707 





86-95 



87-01 i 86-97 



87-08 



87-01 



87-04 



86-96 



87-06 



87-05 





87-03 



187-01 187-12 



87-13 



86-98 



87-06 



87-01 



8706 



87-05 





87-03 



87-05 86-99 



87-05 



87-11 



87-15 



86-99 



87-06 



8702 





87-08 



; 87-10 87-02 



87-05 



87-03 



87-07 



87-04 



87-11 



87-02 





87-00 



87-01 86-99 



87-10 



8701 



87-13 



86-99 



8703 



8702 





87-03 



87-03 87-12 



87-08 



87-03 



87-04 



86-99- 



87-10 



87-02 





86-97 



87-12 













I 



87-03 



87-00 













Mean 



87-00 



87-04 87-05 



8706 



87-04 87-08 87-01 1 87-06 



87-04 



Probable error. 



•010 



•007' -011 



•012 



■007 -007 -004 



•006 -008 



Thermometer .. 



- 



4 2 



2 



2 2 2 2 2 



Ann. C?>im. Phys. [3] Hi. p. 909. 



