22 
BULLETIN 1067, TJ. S. DEPARTMENT OF AGRICULTURE. 
nearly constant as possible, so as to obtain the efficiency under normal 
conditions. Table 13 shows the results of the test. The indicated 
horsepower given in the table is the mean of the two cards taken at 
the beginning and end of each observation. 
Table 13. — First test of pumping plant in Jefferson drainage district No. 3, Lafitte, 
La., Feb. 22-23, 1913. 
UNIT NO. 1, 48-INCH PUMP. 
Speed. 
Indicated 
horse- 
power. 
Discharge. 
Actual 
lift. 
Head 
on 
pump. 
Useful 
water 
horse- 
power. 
Efficiency. 
Pu TO Pump 
Pi$?g. en ^ e - 
E. p.m. 
103 
134.8 
203.5 
121.3 
90.9 
102.2 
137.1 
142.6 
140.7 
Sec.-ft. G.p.m. 
136.6 61,300 
158.6 71,200 
129.8 58,300 
103.8 46.600 
94.6 42.450 
118.3 53; 100 
119.7 .53,750 
122.8 55.100 
Feet. 
4.00 
4.40 
4.80 
4.85 
6.05 
5.35 
5.42 
5,45 
Feet. 
4.05 
4.42 
5.48 
5.87 
6.58 
6.29 
6.23 
6.03 
62.0 
79.2 
70.8 
57.1 
65.1 
71.9 
73.5 
75.9 
Per cent. 
46.0 
38.9 
58.4 
62.8 
Per cent. 
46.6 
39.2 
66.6 
120.5 
101.5 
95.5 
100.5 
63.8 
R9.3 
108 
52. 4 61. 6 
51. 6 59. 4 
54. 59. 8 
108 
109.7 
1105.8 
U34. 1 1123.(1 155.20(1 
15.41 
16.18 
169.4 
1 52. 7 1 60. 3 
UNIT 
NO. 2, 48-INCH PUMP. 
121 
121 
109 
116 
101.7 
93.5 
81.5 
114.5 
212.7 
216.9 
153.4 
185. 5 
125. 5 
95.9 
61.0 
...... 163.8 
170.4 
176. 7 ! 
147. 7 
15S. 7 
133.1 
115.4 
82.9 
122.1 
120.1 
76,500 3.38 4.40 
79,300 3.40 3.00 ' 
66,300 3.31 4.03 
71,250 3.45 5.16 
59,700 3.64 4.01 
51.800 3.84 3.71 
37,200 3.70 4.08 
54,800 6.25 6.84 
53,900 6.85 7.17 
65.4 
68.2 
55.5 
62.1 
55.0 
50.3 
34.8 
86.5 
93.5 
30.7 
31.4 
36.2 
33.5 
43.8 
52.5 
57.1 
52.8 
53.5 
40.1 
35.4 
44.1 
50.1 
48.3 
62.9 
57.8 
55.9 
119 
174.9 
1108.6 
1 154. 4 
1 136. 3 
161,170 16.55 17.00 j 
i 63. 5 
153.2 
156.9 
1 Mean. 
In testing unit No. 1 the actual head at the beginning of the test 
was 4 feet and readings were taken up to 6 feet. It was then found 
that the increase in head was too rapid to get proper readings, due 
to the fact that the only water available for pumping was then in 
the canal. It was therefore decided to siphon water back into the 
canal with No. 2 unit while testing No. 1. This was done for the last 
three observations, and as a result the actual head for those three 
readings was 5.41 feet. The difference between the dynamic and 
static head gives the friction losses in the pipes and at the entry and 
discharge. Several inconsistencies appear in the friction losses 
recorded which can only be accounted for by the fact that it is im- 
possible to make very accurate readings on the suction and discharge 
manometers of drainage units. Velocities were rather high, and the 
suction and discharge pipes were so short that there seemed to be a 
surging effect through the whole system at each revolution of the 
engine corresponding to the variation in angular velocity at different 
parts of the stroke. 
