220 



Injlacnce o the Phjdcal Character 



rainy days when very little rain falls. For one, two, or 

 three (lays, wc have licavy showers, when all the water- 

 courses ai'o flooded. In connexion witli the afore-mentioned 

 ideological formations this is an im])ortant fact. If wc have 

 20 or .'K) showery days, and only of an inch of rain falla 

 in cacli d:iy, we may rest assured that a meagre portion of 

 this will ever ]-cach the rivers. The soil absorbs it rapidly, 

 and it is as rapidly evaporated, though not a])preciable to the 

 eye. Then, if wc have four or five days of heavy rain, with 

 an average of three inclics per diem, this will quickly flow to 

 the river basins^ and produce floods. We are led into error and 

 confusion if we estimate the fall of rain, in a district, at so 

 many feet per annum, Avithout any reference to geology, 

 or to peculiarities of climate. We ought rather to estimate 

 the fall of rain on those days when it is sufficient to flood the 

 creeks. If the annual fall of I'ain in Victoria Avere concen- 

 trated in Ave or six days, I can easily believe that it would 

 nearly all reach the rivers; but, fortunately, our climate is 

 differently arranged. 



In a country Uke this it is not unprofitable to consider 

 every fact, which bears even remotely on the pci'manence 

 of the su])]>ly, or the purity of the Avater. 



In constructing reservoirs in the inland districts^ for sup- 

 plying a town where the ])0]mlatlon is not considerable, in 

 situations where no permanent stream is sufficiently near, it 

 Avill be neccssaiy to resort to filtration on a large scale. This 

 will remove the grosser impurities, but it caiuiot be denied 

 that this fails to remove animalcuhc and chemical impurities. 

 When sup]dled to ]iei'sons who are able to resort to those 

 ai>plia,nccs for purification, taught by the chemist, it becomes 

 comparatively pure, but to the mass of the population it is 

 positively injurious. Whatever can be done to remedy such 

 an evil ought to be done, at any pecuniary sacrifice, for the 

 results c(msc(pient on its removal cannot be overstated in 

 their importance. It Avould be quite ])ossibleto extend these 

 remarks, to ap})ly them in detail to the rivers in our umnc- 

 diate neighbourhood, but this, I fear, Avmdd be merely useless. 

 I have endeavoured, Avith how mnny short-comings I am only 

 too conscious, to indicate to Avhat extent avc are indebted to 

 scientific observations, and to principles founded on the 

 unerring precepts of sciences in all intiuiries of this kind, 

 and to shoAv hoAv ' utterly indefensible it Avould be to rely 

 upon either Avhat is commonly called "experience," or 

 *' practical knoAvledge." 



Science, our hcfpcr in the humblest as in the greatest 



