292 PROCEEDINGS OP THE AMERICAN ACADEMY 



Potassic (3-Sulpho-8-C7ilorpyromucate, KgCsHClSOo. 



The potassium salt crystallizes in long needles which are anhydrous. 



I. 0.9272 grm. air-dried salt gave 0.5309 grm. K2SO4. 



II. 0.8955 grm. air-dried salt gave 0.5126 grm. K0SO4. 



III. 0.7962 grm. air-dried salt gave 0.4562 grm. K2SO4. 



K 



Although there could be little doubt that the sulphonic acid formed 

 from 8-chlorpyromucic acid was identical in structure with the yS-sul- 

 pho-8-brompyromucic acid of Hill and Palmer,* we wished to prove 

 this identity more rigorously by preparing from it by reduction the 

 /8-sulphopyromucic acid. We found that the method employed by 

 Hill and Palmer in the reduction of the bromine compound could 

 successfully be employed in this case, although the chlorine was re- 

 placed with much greater difficulty, and long continued boiling of the 

 ammoniacal solution with zinc dust was essential for complete reduc- 

 tion. We also found it advantageous to convert the baric ^-sulpho- 

 pyromucate into the acid salt, and to purify this by recrystallization 

 from hot water. The neutral salt was crystallized for analysis by 

 evaporation in vacuo over sulphuric acid. 



I. 0.7039 grm. air-dried salt gave 0.4287 grm. BaSOi. 

 11. 1.0434 grm. air-dried salt lost at 100° 0.1476 grm. HgO. J 



Calculated for Found. 



BaCsHoSOs . 3 U„0. I. U. 



Ba 35.96 35.80 



H2O 14.18 14.15 



0.8946 grm. salt dried at 160° gave 0.6347 grm. BaSO^. 



Calculated for BaCcHjSOe. Found. 



Ba 41.90 41.72 



The solubility of the salt in cold water was determined by the usual 

 method. 



I. 14.4785 grm. solution saturated at 21° gave 0.1960 grm. BaS04. 

 II. 12.0525 grm. solution saturated at 21° gave 0.1628 grm. BaSOi. 



The solution saturated at 21° therefore contained the following per- 

 centages of the anhydrous salt : — 



* These Proceedings, xxiii. 214. 



