150 
by any increase. Indeed, the average level for this month at 
Copperas Creek is only 2.82 feet, the lowest average for the 
year. The rises attending this period appear but twelve times 
in twenty-one years, are usually insignificant, and are often less 
than two feet, owing doubtless to the greater capacity of the soil 
for absorption at this season of the year. 
The time not included in the high- and low-water periods 
as here defined amounts on the average to 96 days, a relatively 
short time for the transition between these two extreme condi- 
tions. This abruptness of the transition stages is to some ex- 
tent apparent in the hydrographs. 
On Tables I. and II. will be found tabulations of the total 
movement, both + and —, of the river levels in each month in 
the period covered by the records at the two dams. The 
monthly and yearly averages of these data are also given. The 
figures are to a certain extent an index of the relative stability, 
both monthly and annual, of the river. The averaging process 
has to some degree masked the differences in the several 
months, as will be seen on a comparison of the mean monthly 
movements with those for any single year, the latter exhibit- 
ing at some times of the year much greater contrasts than the 
means. Thus the greatest and least movements in 1897 are re- 
spectively 10.37 feet in January and 0.40 in October, while the 
corresponding limits in the means are 4.18 feet in July and 2.78 
in November. The means indicate two periods; one of consid- 
erable movement, corresponding to that of high water, and one 
of less movement, representing the low-water stages. The 
greatest movements occur in February and July, indicating the 
rise and decline of the flood. The least movement is found in 
November, a period of low water and freedom from sudden and 
heavy rainfall. The several years exhibit quite a range in the 
total amount of change in levels, the extremes in Copperas 
Creek in twenty-one years being 68.70 feet in 1881 and 32.92 in 
1894; at La Grange, in seventeen years, 85.36 feet in 1898 and 
40.41 in 1887. The movement is thus somewhat greater and 
more variable at the lower dam. In general there is some cor- 
