50 



Mr. E. P. Perman. 



[May8, 



a pan of water, and the pressure was made so near the saturation- 

 pressure that the bromine took three hours to vaporise completely. 



Series IV. Temperature, 14- 7 15; Capacity of Globe, 445'6 c.c. 



The vapour-pressure of bromine at 15 is 138' 1 mm., according to 

 the tables of Professors Ramsay and Young (' Chem. Soc. Journ.,' 

 vol. 49, 1886, p. 445). These results show that, on approaching the 

 liquid state, bromine has no tendency to form molecules with more 

 than 2 atoms. This agrees with the results of Paterno and Tasini 

 (' Deutsch. Chem. Ges. Ber.,' vol. 21, 1888, p. 2153) by Raoult's method, 

 which indicated molecules Br 2 in aqueous and acetic acid solutions. 



Series V. Temperature, 279 0< 5 (Bromonaphthalene) ; Capacity of 

 Globe, 448-6 c.c. 





The temperature employed in this series was much higher than tlie 

 temperatures used by Professor J. J. Thomson in his experiments ; 

 some of the pressures were much lower, and the total time of heating 

 was about five hours, yet there was no sign whatever of any 

 dissociation. 



Finally, an experiment was made with bromine in presence of air. 

 The bromine was boiled out of the globe at exactly half the atmo- 

 spheric pressure, and air was then slowly admitted until the pressure 

 inside and out was the same. 



