JESTS OF DRAINAGE PUMPING PLANTS. 49 
for normal plant operations and does not include the 25 per cent 
allowance for starting and lubricating oils. The accuracy of the 
work is limited by the amount of data available. 
It will be noted that curve II does not pass through the point 
plotted for Jefferson drainage district Xo. 3 nor through point for 
subdistrict Xo. 1, Gueydan drainage district, but is drawn between 
them to give probable results for an average plant of this type. It 
must be remembered that the test -of the former plant showed greatly 
unbalanced quantities passing through the two suction pipes. The 
engines are rather large for the pumps, and this doubtless has a 
material effect on economy. On the other hand, the Gueydan 
pumps are volute pumps of much more elaborate design than the 
drainage pumps of Jefferson drainage district Xo. 3. The pumps 
were large and the velocities of water through them comparatively 
slow; all these factors made for lower fuel rate. 
Figure 6 shows the cost per year of pumping 29 acre-inches against 
various lifts, as obtained from the curves of figure 5. For the 
average drainage proposition discussed in this report the lift for 
the first two or three years is approximately 3 feet; later, when a 
part of the humus disappears and deeper drainage is desired, the 
lift is increased to 5 feet or more. The general range of lift was 
from 2 to 8 feet. 
In all the tests recorded oil was used as fuel. In order to make a 
comparison of cost it is necessary to consider the kind of oil used in 
the different plants. The steam plants and the Diesel-engine plant 
No. 20 (fig. 5), either used or could use Mexican crude or some low 
grade of fuel oil. Prices of fuel oil have fluctuated considerably 
during the last seven years. During 1919 and 1920 the price of oil 
delivered at Xew Orleans has ranged from about 75 cents to S3. 50 
per barrel. The prices of distillates and kerosene have shown 
variations that make it impossible to arrive at a probable cost for 
the future because of the great instability of prices. 
The average price of the lower grade of fuel oil delivered at the 
pumping plant for the years 1912-1917 was about $1.10 per barrel 
of 42 gallons. For hot-bulb engines of the semi-Diesel type a higher 
grade of crude oil is required. The price for this oil delivered at 
pumping plants for the same period ranged from SI. 40 to SI. 80, 
with the average about SI. 60. 
Some internal-combustion engines, such as those in plants Xo. 
8 and Xo. 10, are supposed to use a distillate of low grade, costing 
about the same as the fuel oil used in the semi-Diesel engines. In 
some instances distillate has been mixed with kerosene to make a 
more satisfactory fuel. Plants Xos. 8 and 10 may be operated in 
this way. Plant Xo. 9 uses kerosene. The cost of distillate deliv- 
