194 PROCEEDINGS OF THE AMERICAN ACADEMY 



I. 0.3232 grm. substance gave 0.1289 grm. COg and 0.0230 grm. 



H,0. 

 II. 0.4060 grm. gave 0.1858 grm. PbSO^. 

 III. 0.4908 grm. gave 0.2230 grm. PbSO,. 



Calculated for PbCCjHBrjOj),. . Found. 



I. n. in. 



10.86 

 0.79 



31.27 31.05 



Calcic Dlbromacrylate, Ca(C3HBr20^)2.3H20. On neutralizing a so- 

 lution of the acid with calcic carbonate, and concentrating the solution 

 on the water bath, the calcium salt was obtained in clusters of radiat- 

 ing needles, tolerably soluble even in cold water. The salt gradually 

 effloresced over sulphuric acid, and lost its crystal water completely at 

 80-85°. 



0.7342 grm. of the air-dried salt lost, at 80-85°, 0.0695 grm. of HjO. 



Calculated for Ca-iC^WRv^O^)^ . SHjO. Found. 



H^O 9.78 9.47 



0.4951 grm. of the salt, dried at 80-85°, gave, on ignition with HjSO^, 

 0.1354 grm. CaSO^. 



Calculated for Ca(C3nBr202). Found. 



Ca 8.03 8.04 



Potassic Dibromacrylate, KCgHBr^Og. The acid neutralized with 

 potassic carbonate and evaporated gave, on cooling, crystals of the 

 potassium salt. From neutral solutions it crystallizes in transparent, 

 six-sided, clustered plates. If but a small amount of free acid is 

 present, it crystallizes in fine, felted needles. Both forms are anhy- 

 drous, and do not lose in weight at 80°. 



0.5506 grm. gave, on ignition with HgSO^, 0.1792 grm. K2S0^. 



Calculated for KCaHBrjOj. Found. 



K 14.58 14.61 



An acid salt much less soluble in water may be made by adding 

 acid to a solution of the potassium salt. It crystallizes in long needles, 

 which are aniiydrous. The salt is not particuLarly stable, and the 

 excess of acid may be washed out with ether. The salt was dried by 

 exposure to the air, after several recrystallizations from hot water. 



I 



