194 Compound of Dibromallylammonia and Chloride of Mercury. 



from the entire mass of geological inquiries; hence, as far as 

 observation enables us to judge, we cannot explain by superficial 

 actions alone the twofold condition — of the spheroidal shape in 

 the earth's figure, and the gradual diminution of its surface 

 temperature from the earliest periods of geological history down 

 to the most recent. 



XXIX. On a Compound of Dibromallylammonia and Chloride of 

 Mercury. By Dr. Maxwell Simpson*. 



IN a paper published in this Journal (October 1858) on the 

 Action of Ammonia on the Terbromide of AUyle, I men- 

 tioned that dibromallylammonia forms a compound with chloride 

 of mercury. This compound I have since studied ; the following 

 are the results. 



The body in question makes its appearance in the form of a 

 white voluminous precipitate, on mixing alcoholic solutions of 

 dibromallylammonia and of chloride of mercury, keeping the 

 latter in excess. The excess of chloride can be afterwards re- 

 moved by washing the compound with watei-, in which it is 

 almost insoluble. The body thus prepared was submitted to 

 analysis, having been previously well dried in vacuo over sul- 

 phuric acid. 



The following numbers were obtained : — 



I. 0-4130 grm. compound gave 0"2138 grm. carbonic acid 

 and 0-0781 water. 



II. 0-5052 grm. compound gave 0-2268 grm. sulphuret of 

 mercury. 



III. 02690 grm. compound gave 0-1562 grm. chloride of 

 silver f. 



IV. 0*4446 grm. compound, heated with quicklime, gave 

 0-5534 grm. mixed chloride and bromide of silver; and 05123 

 grm. of this mixture lost 00676 grm. on passing chlorine 

 over it. 



rcen^Br 



These numbers agree with the fornmla 2 (HgCl) + N -j C^^H^Br, 



rcm^Br"] L H 



or perhaps HgCl + N^ C^^H^Br IhCI, as will be seen from the 



L Hg J 

 following per-centage Table : — 



* Communicated by the Author. 



t This determination was made by dissolving the compound in dilute 

 nitric acid and adding nitrate of silver. The chlorine was alone precipi- 

 tated, the bromine remaining in solution. 



