242 The Data on which we have to depend 
is less than the English proportion. From the want of ex- 
tended meteorological observations taken in connexion with 
the Upper Plenty districts, or, what would have been much 
more satisfactory, a complete series of stream guagings to 
determine the annual discharge, ,the available rainfall of the 
district can only be analogically eliminated from the general 
data afforded by the most trustworthy English observations 
on evaporation, corrected for the average differences of tem- 
perature, for the various months in the year, in London and 
Melbourne, as given in the Statistical Register for Victoria. . 
Moreover, as wind and the hygrometrical state of the atmo- 
sphere exercise a marked influence over evaporation, inde- 
pendently of temperature, and as their action 1s more intense 
here than in England, some additional corrections must be 
applied to the English data for this increased action. Having 
made due allowance for all these contingencies, I have 
arrived at the conclusion that the total annual rainfall and 
dew at the Upper Plenty may be taken together as equi- 
valent to thirty-six inches, and that the amount thereof avail- 
able for the supply of the Plenty, in the present state of the 
natural surfaces, would be about five inches.” 
I entirely concur with the opinions expressed in the above 
paragraph, but, in adopting for the Upper Plenty district a 
larger proportion of available rainfall than is relied on for 
the average surface of England, Mr. Hodgkinson has alto- 
gether forgotten the principles which he has so ably incul- 
cated. 
He admits that the proportion of the rainfall in the Upper 
Plenty district ought to be less than the English proportion : 
Why does he not, therefore, adopt less than the Hnglish 
proportion? He admits the want of meteorological obser- 
vations, and that measurements of the river would have been 
much more satisfactory: Why does he not base his calcula- 
tions on the December measurements, making due allowance 
for the winter rains ? 
He tells us that his estimate of the available rainfall of 
the Upper Plenty District is only analogically eliminated 
from English data, corrected in a very complicated manner 
for temperature and dry winds. How is it then that he 
places such implicit confidence in an estimate so singularly 
enveloped in difficulties and uncertainties, and applied under 
novel circumstances to a pew country, with a totally different 
climate? And after all he has not made the corrections to 
which he attaches so much importance. He has adopted a 
less proportion of available rain than Mr. Howard’s, which 
