OF ARTS AND SCIENCES. 245 



of titvition described above may perhaps find useful application in 

 technical laboratories, as the end reaction in titrating with hyperman- 

 gauate is not very sharp. I have in my work employed it in several 

 cases as a check upon other methods. 



In the analyses of vanadio-molybdates it is best to determine the 

 alkalies by difference, as in the cases of the phospho-molybdates and 

 phospho-tuugstates. As in these cases also ammonia and water are 

 best determined together by ignition with a weighed portion of neutral 

 sodic tungstate, WO^Na^, a method suggested by Dr. F. A. Gooch 

 for the whole class of phospho-tuugstates and phospho-molybdates of 

 ammonium ; only in the case of the vanadio-molybdates and other salts 

 containing both molybdenum and vanadium, it is necessary to be espe- 

 cially careful in igniting with the tungstate, because molybdic teroxide 

 is sometimes given off before the complete fusion of the tungstate with 

 the salt. 



6:1 Series. — A solution of ammouic meta-vanadate, YOgNH^, 

 readily dissolves molybdic teroxide on boiling, forming a deep orange- 

 yellow solution. The liquid on standing deposits a veiy beautiful 

 lemon-yellow salt, in sharp octahedral crystals, which are soluble in 

 a rather large excess of cold water without sensible decomposition. 

 The solution, on spontaneous evaporation, yields the salt without 

 change. Of this salt, — 



1.1349 gr. lost on ignition with WO.Na, 0.1806 gr. = 15.91% 

 1.3220 gr. " " « " ' 0.2128 gr. == 16.09% 



1.5022 gr. « " « " 0.2412gr. = 16.05% 



1.2477 gr. gave 0.2201 gr. NH.Cl = 8.57% (NHJ^O 



1.3822 gr. " 0.2439 gr. " = 8-57% " 



1.2847 gr. " 0.1893 gr. V^O. by KMnO^ = 14.73% 



The analyses lead to the formula 



6 M0O3 . Y^O, . 2 (NH,\0 -f 5 aq, 

 which requires : — 



7.48 



1241 100.00 



