PRESIDENTIAL ADDRESS. 47 
Sewage Disposal.—The most recent improvement in 
this direction is the introduction of the septic tank by 
Cameron at Hxeter, Hngland, in 1896, which proved that 
a closed tank, through which sewage passed slowly, was 
a means by which not only the amount of suspended 
organic matter in sewage could be greatly reduced, 
but a partial purification of the sewage brought about. 
Experimental septic tanks were afterwards built in many 
places in England—first closed tanks similar to the one 
at Exeter, then open tanks, and to-day septic tanks, 
closed or open, are recognised as an essential part of 
modern bacterial purification processes. An excellent 
report on this subject has been recently published by 
the Government Printer, namely: “‘ Report on the latest 
methods in use in the United Kingdom and elsewhere 
on Sewage Purification and Disposal,’ by J. Davis, 
M. Inst. c.E, Under-Secretary for Public Works, formerly 
Engineer-in-Chief for Sewerage Construction. 
In nearly every case the septic tank is a valuable 
adjunct to the method of intermittent filtration and an 
essential adjunct in the methods of treatment by contact 
beds and percolating filters. 
New South Wales Government Railways.—The most 
important works carried out in connection with the Per- 
manent Way Department of the Railways may be sum- 
marised as comprising improvements of grades and curves; 
duplication of existing lines; strengthening of existing 
lines; strengthening of old bridges; the provision of new 
buildings for locomotive and traffic purposes, and the pro- 
vision of extensive water supplies to meet increasing con- 
sumption of water by the Locomotive Department. 
Improvement of Grades and Curves.—In regard to 
improvement of grades the practice has been to deal with 
such steep grades as ruled, the loads that could be hauled 
