NEPEAN WATER ON TUBES AND BOILER PLATES. 



193 



Cyathea medullan's, Swartz. 



Pteris aqnih'na, Linn. (" Brake fern" or " Bracken.") 



" Stenhouse's alkaloid" from. An7i. F harm. \xx. 200 ; Gmeli'n, 



X. 410. 

 Pteritannic acid and derivatives. Luck, Jahrb. prackt. 



Fharm.xxn. 173 ; Gmelin. xv. 500-4 ; Watts' Diet., iv., 745. 

 Asplenium nidus, Linn. (" Bird-nest fern.") 

 Platycerium alcicoime, Desv. ("Elk-horn fern.") 

 P. grande, J. Smith. (" Stag-horn fern.") 

 " On the inorganic constituents of some Epiphytic ferns." W. 



A. Dixon, Proc. R. S., X.S.W., 1881, 175. 



8._0N THE ACTION OF THE NEPEAN WATER ON 



TUBES AND BOILER PLATES, WITH SOME 



REMARKS ON CORROSION GENERALLY. 



By William M. Hamlet, F.I.C, F.C.S., Analyst to the New 

 South Wales Government, Sydney. 



A water of undoubted purity, so far as regards its use for dietetic 

 purposes, may still be unsuitable for steam boilers, especially 

 those complex tubular boilers of modern construction where 

 dissimilar metals in contact, are frequently exposed to its 

 continuous action. Such a water is that used for the water supply 

 of the city of Sydney. This water may be justly described as a 

 non-polluted upland surface water, derived from non-calcareous 

 strata. 



The sanitary-chemical analysis of the water is as follows : the 

 figures being the mean of a series of analyses made at different 

 periods — 



