208 PROCEEDINGS OF THE AMERICAN ACADEMY 



We also determined the solubility of the salt in water at ordinary 

 temperatures. Since the hot saturated solution deposited little or 

 nothing on cooling, we prepared the solution by boiling down the hot 

 aqueous solution until the salt began to separate. On cooling this 

 supersaturated solution, abundant crystals were deposited. 



I. 32.6032 grm. of the solution saturated at 20° gave 0.5016 grm. 

 BaS0 4 . 

 II. 33.7864 grm. of the solution saturated at 20° gave 0.5194 grm. 

 BaS0 4 . 



The aqueous solution saturated at 20°, therefore, contained the fol- 

 lowing percentages of the anhydrous salt : — 



i. n. 



2.68 2.68 



Acid Baric fi-Sulpho-b-brompyromucate, Ba(C 5 H 2 BrS0 6 ) 2 . 4 H 2 0. — 

 This salt is most easily prepared by dissolving the neutral barium salt 

 in diluted hydrochloric acid. It is readily soluble in hot water, spar- 

 ingly in cold water, and crystallizes in large well-formed prisms, which 

 appear to be triclinic. The salt loses nothing when exposed to the 

 air, or over sulphuric acid, and the loss at 100° is also insignificant. 

 At 130° it slowly loses in weight, but turns brown and suffers partial 

 decomposition before complete dehydration is reached. 



I. 0.7884 grm. of the air-dried salt gave 0.2456 grm. BaS0 4 . 

 II. 0.7804 grm. of the air-dried salt gave 0.2460 grm. BaS0 4 . 



Ba 



Calcic fi-Sulpho-8 brompyromucate, CaC 5 HBrS0 6 . 2 H 2 0. — The 

 calcium salt is quite readily soluble in cold water, and its solubility is 

 but little increased by heat. It crystallizes in compactly aggregated 

 oblique prisms, which are permanent in the air, and lose but little in 

 weight over sulphuric acid or when heated to 100°. 



I. 1.7804 grm. of the air-dried salt lost, at 205°, 0.1767 grm. H 2 0. 

 II. 0.6483 grm. of the air-dried salt gave 0.2544 grm. CaS0 4 . 



Found. 



II. 



11.54 



