LVIII. BR. T. McKAY. 
and in reducing evaporation to a minimum, must have a marked 
influence in increasing the seepage run-off and decreasing the 
surface flow. Observations made in various parts of the world 
show that evaporation from water or other wet surfaces on 
the floor of a forest is but one-third or one-fourth that from 
similar surfaces is unforested areas. 
Relation of Rainfall to Run-off of Murrumbidgee 
Catchment at Gundagai._In 1884 Mr. T. A Coghlan, 
Assoc. M. Inst. C.E. read a paper before the Institution of Civil 
Engineers, entitled “‘ Discharge of Streams in Relation to 
Rainfall,” in which he dealt very fully and ably with the 
discharges and rainfall of the Sydney Water Supply 
Catchment, but so far as the author is aware, no attempt 
has previously been made, up to the time of the 
commencement of his researches, to determine the relation 
of rainfall to run-off of the more important rivers in the 
interior of New South Wales. 
The Murrumbidgee River.—Theauthor has devoted much 
time to the collection of data, in order to show the volume 
of water available from the gathering grounds of the 
Murrumbidgee River, one of the most important waterways 
in the State. The Murrumbidgee rises in the high 
mountainous ranges, its source being near Kiandra. The 
river continues its course through hilly country for about 
300 miles until the town of Gundagai is reached, thence to 
Narrandera, a distance of 280 miles, it flows through 
undulating country, and thence its course to the confluence 
of the Murray is through flat country, the lower reaches of 
Which are liable to inundation. The highly effective 
catchment ends at Gundagai, a short distance below the 
confluence of an important tributary, the Tumut River, 
and the author has endeavoured to show the relation of 
rainfall to run-off of the drainage area at this point, it 
being the highest station on the river at which accurate 
stream measurements have been taken, and also being not 
