Dr. E. J. Mills's Researches on Melting-point. 5 



4. Dinitrobromobenzol. — Benzol purified by bromine distil- 

 lation, and freezing, was brominated by the Conper process, 

 and freed from dibromobenzol by beating to the boiling-point 

 with a mixture of Nordhausen and common oil of vitriol ; 

 this treatment was followed by washing and distillation. 



Sample A was prepared from the above bromobenzol by 

 Kekule's method*. The crude product amounted to 148 per 

 cent., theory requiring 157 per cent. : it contained a small 

 quantity of an oily body. This was crystallized twice from 

 naphtha and five times &c. (A 5 &c.) from alcohol. 



The crystals of dinitrobromobenzol are, as observed by 

 Kekule, remarkably large and well defined. They powder 

 harshly, like rosin. The concentrated alcoholic solution emits 

 sound as it crystallizes. 



Dinitrobromobenzol melts with considerable sharpness. 



Table IV. 





A. 5 . 



A 6 . 



A,. 



A, 



As. 



1 

 Ajo- ! A 10 . 





o 







o 



o 



o 







7053 



70-54 



70-56 



70-68 



70-67 



70-68 70-56 





•53 



•51 



•64 



55 



•54 



•71 



•59 





•50 



•65 



•61 



•55 



•64 



•55 



•53 





•53 



•49 



•64 



•55 



•67 



•71 



•53 





•48 



•51 



•56 



•57 



■54 



•55 



•56 





•53 



•57 



•67 



•68 



•70 



•60 



•66 





•61 



•51 



•59 



•57 



•56 



•60 



•66 





•58 



•65 



•59 



•68 



•64 



•63 



•56 





■66 



•59 



•48 



•57 



•59 



•68 



•46 





•53 



•57 



•67 



•68 



•59 



•60 



•69 





•64 



•54 



•69 



•63 



•67 



•57 



•71 





•48 



•54 



•67 



•65 



•62 



•68 







•50 



•67 



•64 



•63 



•67 



•57 







•56 



•62 



■67 



•63 



•67 



•57 





Mean 



70-55 



70-57 



70-62 



70-61 



70-62 



7062 



70-59 



Probable error . . . 



•010 



•010 



•010 



•009 



•009 



•010 



•015 



Thermometer . . . 



2 



2 



2 



2 



2 



2 j 3 



5. Nitrodibromobenzol. — Sample A, from (D) dibromobenzol 

 (q. v.) which had been crystallized once from alcohol, once 

 from naphtha, and once from alcohol. 25 grm. of substance 

 were gently heated with 250 cub. cent, of "fuming nitric 

 acid," and allowed to cool during a rather longer period. The 

 product, purified by means of water and ammonia, contained a 

 little oily impurity, and weighed 28*5 grm. ( = 114 per cent., 

 theory requiring 119*1 per cent.) : it was crystallized twice 

 from naphtha, and thrice &c. (A 3 &c.) from alcohol. 



* Ann, Chem, Pharm, cxxxvii. p. 167. 



