XXVI. J. HAYDON CARDEW. 



2. The systematic gauging of creeks, and rivers, noting the 



occurrence of floods and determination of flood heights 

 and stream discharges. 



3. The measurement of evaporation from land and water. 



4. Determination of percolation in (different soils and strata. 



5. Determination of efflux or run off from catchments. 



6. Recording phenomena of artesian boring. 



7. Recording tidal phenomena and determination of mean 



sea level. 



In connection with the ascertainment of the rainfall it 

 is necessary to fix the altitude of the rain gauge above sea 

 level, that comparison may be made of the effect on the 

 rainfall of difference of altitude, and also the distribution 

 of the rainfall should be carefully noted for different seasons 

 of the year. In connection with the determination of efflux 

 from catchments and the torrential character of a basin it 

 would be necessary to define the area of each creek and 

 river catchment, classifying the areas consisting of flat 

 impermeable strata, sloping impermeable strata, and im- 

 permeable strata with notes as to vegetation and cultiva- 

 tion ; the statistics of each valley of the basin should be 

 separately recorded in order that the nature of flow of each 

 tributary of a river and the influence of the tributary on 

 the main river may be studied if necessary. In addition 

 to the tabulation of the data thus obtained, the preparation 

 of maps of the river basins illustrating by suitable shading 

 the nature of the strata and the distribution of the rainfall 

 would convey a great deal of useful information at a glance. 



With regard to the observations for rainfall, I have 

 already said that for the benefit of the engineer the observ- 

 ing stations require to be greatly increased ; at the present 

 time there are 1,724 official rain gauges in New South 

 Wales, and as the area of the State is 310,700 square miles, 

 they average only one to each 180 square miles, this pro- 



