NITRATES IN WATER. 325 



12.— GOLD MOIRE-METALLIQUE. 



By Professor LIVERSIBGE, M.A.. F.R.S. 

 (See Proc. Roy. Soc, N.S.W., 1893.) 



13.— A COMBINATION LABOUATORY LAMP, RETORT, 

 AND FILTER STAND. 



By Professor LIVERSIBGE, M.A., F.R.S. 

 (See Proc. Roy. Soc, N.S.W., 1893.) 



14.— RESULTS OF ANALYSIS OF SOME SOUTH 

 AUSTRALIAN WATERS. 



By G. GOYDER, Jim., F.C.S. 

 (See Proceedings of Section I.) 



-o-«-o- 



15.— NOTE ON THE DETERMINATION OF NITRATES 

 IN THE ADELAIDE WATER. 



By E. H. REXXIE, M.A., D.Sc, and E. F. TURNER. 



Some time ago Warrington (C.S. J., xxxv., 377) made some experi- 

 ments which went to prove that in determining nitrates in potable 

 waters by the nitric oxide method it was not necessary, as intimated 

 by Frankland, to remove any chlorine which might be present, but 

 that, on the contrary, in some cases at any rate, the presence of 

 chlorine was distinctly beneficial. In examining samples of the 

 Adelaide water supply, we have made some observations which 

 seem to confirm Warrington's results. The Adelaide water con- 

 tains so much chlorine as to render it imjjossible to use the 

 evaporation residue for the evolution of nitric oxide unless the 

 chlorine be first removed, because of the large quantities of hydro- 

 chloric acid evolved. In our experiments, therefore, we first 

 completfly removed the chlorine in the usual manner, filtered off the 

 silver chloride, evaporated the filtrate to dryness, took up in a very 

 small quantity of water, and again filtered to remove some silver 

 reduced by the action of organic matter on the excess of silver 

 sulphate. In several experiments made in this way no nitric oxide 

 was evolved on shaking with mercury and sulphuric acid in the 



