158 
DE. J. P. JOULE ON THE SUEEACE- CONDENSATION OF STEAM. 
Table II. — Atmospheric Air, the refrigerating agent, 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
Dura- 
tion of 
Total 
pressure of 
Pressure 
required 
Mean temperature of 
the refrigerating air. 
Description. 
No. 
experi- 
steam in the 
boiler, in 
inches of 
to propel 
the air, in 
inches of 
ment, in 
minutes. 
mercury. 
water. 
entrance 
At its exit 
(t). 
(^i). 
Copper steam-tube 4 feet long. Exterior diameter 0'75 
inch, interior 0-63 inch. 
Outer tube 0'8 inch interior diameter. 
1 
60 
60 
73-3 
231 
13-83 
13-83 
94-12 
72-16 
201 
90-49 
2 
3 
60 
82-1 
228 
19-03 
99-4 
The same copper steam-tube. 
Outer tube 0 87 inch interior diameter. 
4 
48 
62-74 
31-8 
13-18 
81-64 
5 
60 
73-16 
31-48 
14-4 
86-3 
The same copper steam-tube. 
Outer tube 1 inch interior diameter. 
6 
60 
51-23 
1-36 
10-94 
80-64 
7 
60 
43-58 
3-5 
12-53 
76-83 
8 
60 
41-64 
3-5 
13-86 
73-7 
9 
60 
41-51 
5-52 
11-74 
72-84 
10 
60 
46-53 
5-52 
11-38 
72-86 
The same copper steam-tube. 
Outer tube interior diameter T4 inches. 
11 
48 
43-67 
5-52 
10-26 
42-07 
12 
60 
53-16 
5-52 
8-8 
43-44 
13 
60 
48-9 
5-52 
9-47 
44-2 
14 
60 
42-33 
1-28 
10-48 
48-47 
15 
60 
49-05 
1-3 
10-93 
49-88 
The same tubes. A spiral of 30 turns of copper wire 
J^th inch thick was wound roimd the steam-tube. Half 
16 
60 
43-54 
1-3 
10-57 
73-58 
of this spiral was right-handed, the other half left-handed. 
17 
60 
42-32 
5-32 
14-87 
67-29 
Copper steam-tube 2 feet long. Exterior diameter 
0-75 inch. Outer tube T4'inch interior diameter. 
18 
60 
41-76 
1-44 
9-13 
69-13 
A spiral of 20 turns of copper wire 0'21 inch thick 
between the tubes. 
19 
60 
46-88 
3-55 
8-46 
63-33 
^Copper steam-tube 1 foot long. Exterior diameter 
0'7o inch. Outer tube T4 inch interior diameter. 
20 
60 
45-04 
1-44 
6-43 
52-87 
A spiral of 10 turns of copper wire 0-21 inch thick 
between the tubes. 
21 
60 
45-06 
3-55 
8-23 
46-73 
