OF ARTS AND SCIENCES. 117 



acid, but I could not obtain it in a state of purity sufficient for 

 analysis. It may be worth wliile to note as a possible source of differ- 

 ence, that Scheibler obtained his acids by the decomposition of the cor- 

 responding barium salts by dilute sulpliuric acid. The method of 

 preparation which I employed is, I think, preferable. 



24 : 2 Acid Sodic Phospho-tungstate. — AVhen chlorhydric or nitric 

 acid is added in large excess to a solution of normal sodic tungstate, 

 and of hydrodisodic phosphate containing 24 molecules of the former 

 to 2 of the latter, a salt is obtained which is usually colorless when 

 chlorhydric acid is employed, and pale sulphur yellow when nitric 

 acid is used. This salt crystallizes more easily than the other salts of 

 sodium. According to Dr. Gooch, the small granular crystals appear 

 to be either monoclinic or triclinic. They are readily soluble in water, 

 but invariably undergo a slight decomposition in the act of solution, a 

 small quantity of a white crystalline powder being formed which is in- 

 soluble, or but slightly soluble. The yellow and the colorless crystals 

 have the same crystalline form and the same reactions. Their consti- 

 tution is also the same, as the following analyses show : — 



I. 



1.4900 gr. lost on ignition 0.1107 gr. water 

 1.1100 gr. gave 1.0016 gr. WOg + PgO- 



1.8072 gr. " 0.0679 gr. l\O^Mg^ 



II. 



0.9913 gr. lost on ignition 0.1809 gr. water 

 0.8945 gr. « « 0.0658 gr. " 



1.0745 gr. gave 0.9698 gr. WO3 + P^O., 



1.1508 gr. " 0.0420 gr. PgO.Mg^ 



III. 



1.4933 gr. lost on ignition 0.1115 gr, water 

 1.3273 gr. gave 1.19G9 gr. WO3 + PgO^ 



1.5424 gr. " 1.3920 gr. " 



1.2990 gr. " 0.0470 gr. PgO^Mg^ 



1.1503 gr. « 0.0428 gr. " 



IV. 



1.8027 gr. lost on ignition 0.1349 gr. water 

 1.1559 gr. " " 0.0860 gr. " 



1.1269 gr. gave 1.0151 gr. WO3 + P2O6 



0.9624 gr. « 0.0367 gr. PA^^ga 



0.6787 gr. « 0.0263 gr. 



