58 National Geographic Magazine. 
In connection with Professor Russell’s work it is desirable to 
note that Professor F'. E. Nipher has lately made a report on the 
Missouri rainfall based on observations for the ten years ending 
December, 1887, in which he points out as an interesting coinci- 
dence that the average annual discharge of the Missouri river 
closely corresponds in amount to the rainfall which falls over 
the State of Missouri. From Professor Nipher’s figures it 
appears that the discharge of the Missouri river in the ten years 
ending 1887, was greatest in 1881 and next greatest in. 1882, so 
that the averages deduced from Professor Russell’s report of the 
outflow of the Missouri are too large, and should be somewhat 
reduced to conform to the average conditions. In different years - 
the average of the discharge in the outflow of the Missouri 
varies largely, as is evidenced by the fact reported by Professor 
Nipher, that the discharge in 1879 was only 56 per cent. of the 
outflow in 1881. | 
In New South Wales, under the supervision of H. C. Russell, 
Esq., government astronomer, the question of rainfall and river 
discharge has also received careful attention, especially in con- 
nection with evaporation. The observations at Lake George are 
important, owing to the shallowness of the lake (particularly at 
the margin); its considerable surface area (eighty square miles), 
its moderate elevation (2,200 feet), and the fact that it is quite 
surrounded by high lands. Observations of the fluctuations of 
this lake have been made from 1885 to 1888, inclusive. In the 
latter year the evaporation was enormous, being 47.7 inches 
against a rainfall of 23.9 and an in-drainage of 5.3 inches, so that 
the total loss in depth was 18.5 inches for the year. It appears 
that the evaporation in different years on this lake varies as 
much as 50 per centum of the minimum amount. According to 
Russell the amount of evaporation depends largely on the state 
of the soil, going on much faster from a wet surface of the 
ground than from water; with dry ground the conditions are 
reversed. In 1887, the outflow from the basin of Lake George, 
the drainage from which is not subject to loss by long river 
channels, was only 3.12 per centum of the rainfall. 
In the Darling river, above Bourke, says Russell, the rainfall 
is measured by 219 gauges. The average river discharge, 
deduced from observations covering seven years, is only 1.45 per 
centum of the rainfall, and in the wettest year known the dis- 
charge amounted only to 2.33 per centum of the rainfall, and has 
