212 
71bs., it is less marked thaa when the discharge is made 
through D. 
Suspecting that the phenomenal change in the rate of 
discharge for the same orifice was due to the varying resist- 
ances of the discharging and receiving atmospheres of 
pressure described in my former paper, the discharges from 
the orifices 0, A, and D. were made into a vacuum of 1%5 
inches of mercury instead of into the atmosphere, and the 
times of discharge were recorded for each reduction of lib. 
of pressure. 
The results are shown in the table. 
Table III. 
Discharge into a Vacuum 1'5 inches Mercury, 
Lbs. per 
square inch 
absolute 
pressure. 
Hole in 
O thin plate. 
^ Plain tube 
> Orifice. 
Conoidal 
y Orifice 
Inside. 
Conoidal 
y Orifice 
Outside. 
Coefficient 
O for 
Orifice. 
15 
16-0 
15-0 
16-0 
16-0 
•937 
14 
17-5 
16-5 
18-0 
18-0 
•943 
13 
19-0 
17-5 
20-0 
20-0 
•921 
12 
21-0 
19-5 
22-5 
22-0 
•928 
11 
23-0 
23-5 
24-5 
24-0 
•935 
10 
25‘5 
24-0 
27-5 
27-0 
•941 
9 
28-5 
27-0 
31-0 
30-5 
•947 
8 
32-5 
31-0 
35-5 
35-0 
•954 
7 
37-5 
35-5 
41-0 
40-0 
•947 
6 
45*0 
42-5 
49-5 
48-5 
•944 
5 
55-0 
52-5 
63-0 
61-0 
•955 
4 
70‘0 
67-0 
81-0 
79-0 
mean 
3 
102-0 
101-0 
125-0 
120-0 
coeffi - 
cient 
2 
180-0 
192-0 
241-0 
224-0 
•941 
A comparison of the times of discharge through D with 
the conoidal orifice in both positions will show that they 
approach nearly to a ratio of equality. The phenomenal 
change in the rate of discharge from the same orifice was 
consequently due to the diminished resistance of the 
