52 Dr. Maxwell Simpson on the Brom-Iodides. [Jan. 8, 



of olefiant gas into the foregoing solution, which was kept cold during 

 the absorption of the gas. An oily liquid soon made its appearance, 

 which was the body in question ; it was then subjected to distillation, 

 having been previously washed with dilute potash, and afterwards with 

 distilled water. Almost the entire quantity passed over without decom- 

 position between 162 and 167 Cent. This gave on analysis the follow- 

 ing numbers : 



%heo B ry L Experiment. 



C 10-21 10-35 



H 1-70 1-79 



At the temperature of the air this is a solid body, consisting of a mass 

 of long white needles, which melt at 28 Cent. At 29 it has a specific 

 gravity =2-516. It has a sweet biting taste ; on exposure to light it 

 becomes slightly coloured, from the separation of free iodine. When 

 subjected to the action of alcoholic potash, it yields iodide of potassium 

 and a gas burning with a green flame, which is doubtless bromide of 

 vinyl. It is an isomer of the brom-iodide obtained by Pfaundler*, and 

 afterwards by Eeboult, by exposing bromide of vinyl to the action of 

 hydriodic acid. Pfaundler's compound boils between 144 and 147 Cent. 



Brom-iodide of propylene. This body was formed bypassing propylene 

 gas derived from iodide of allyle into the brom-iodine solution. It was 

 washed with dilute potash, then with water, and distilled. The greater 

 part passed over between 160 and 168 Cent., suffering, however, at the 

 same time slight decomposition. The distillate was then analyzed, having 

 been previously agitated with mercury to remove free iodine. The fol- 

 lowing are the results : 



?K L Experiment. 



C 14-46 14-89 



H 2-41 2-77 



Notwithstanding the difference between the theoretical and experi- 

 mental numbers, I believe this is a definite compound, and not a mixture 

 of bromide and iodide of propylene. The discrepancy probably arises 

 from the slight decomposition which the body suffered during distillation. 



Brom-iodide of propylene is, when freshly prepared, a colourless oily 

 liquid ; it has a sweet and biting taste. Treated with alcoholic potash, 

 it yields iodide of potassium and brom-propylene (C 3 H. Br). 



lodo-dibrom-vinyl. When the brom-iodine solution and bromide of 

 vinyl are brought into contact, direct combination takes place, and this 

 body is formed. In order to complete their union, it is advisable to 

 heat them gently in a sealed tube. A portion of the oily product thus 

 obtained was washed with potash and distilled ; almost the entire quan- 

 tity passed over between 170 and 180 Cent. As, however, it suffered 



* Jahreabericht, 1865, p. 483. t Ibid. 1870, p. 439. 



