Bull. U. S. F. C. 1896. (To face page 275.) 
Zisi of the 'tceighU of the main enffinee. 
Cast iron : Pounds. 
2 condenser covers 2, 738 
1 condenser 12,010 
4 cylinders 14,820 
1 bed-plate 15,412 
2 “piuch-wheels” (couplings) 3.210 
2 " crank-wheels” (couplings) 3.270 
4 slide-valves 
1 double air-pump and bed 2,750 
4 steam -chests 2,5W 
4 steam-chest covers 2, 
4 pistons 
4 line-shaft couplings 
12 thrust-collars 2,2(50 
4 cylinder-heads 2,509 
2 stern-bearings 
2 thrust-bearings 2, 655 
2 throttle-valve chambers 448 
2 screw propellers 8,070 
2stern-pipes 1,376 
Bronze castings: 
4 tube sheets (condenser) 4, 098 
2 stern-busliings 257 
2 shaft bushings 003 
2 air-pump plungers 1,05)0 
0 link-blocks 101 
Phosphor bronze ca.stings; 
(5 lower boxes for crank-shaft. — 836 
Iron forgings: 
2 shafts 19,043 
4 bangers 5,480 
4 connecting-rods 2,200 
4 straps, gibs, and keys 654 
4 double-cranks 7, 680 
4 crank-pins 990 
4 cftupling-piQS 764 
0 valve-stems 590 
5 links 786 
Air-pump connections 1,071 
Levers and arms 731 
Guides 843 
12 eccentric rods 1,202 
4 “cylinder braces” (stmts) 1,1(M 
Link connections 295 
Steel forgings: 4 piston-rods 1,877 
Brass tubes: 2,400 drawn-brass con- 
denser-tubes 4,972 
Copper pipe: Steam, feed, and blow 
pipes 3,458 
Reversing ^ear: 2 steam cylinders, 
valves, guide.s, rods, anns, etc 2,270 
Circulatiog-piiinp: 1 Davidson light- 
service pump. No. 28 2,600 
Arlditional weights; 
Floor-plates, flanges, ca.st-iron ex- 
hau.st-pipes, bolts, nuts, etc., used 
inflttingup 48,017 
No. 5 Davidson pump 1,100 
No. 5 David.son light-service pump. £00 
No. 2 Davidson high-pressure pump 250 
No. 1 David.son high-pressure pump 200 
No. 1 Davidson high-pressurepuiiip 200 
Total 203,284 
Plate X. 
Principal dimensiotis of the engines. 
Number of cylinders to each engine 
Diameter of bigh-pressure cylinders inches.. 
Diameter of high-pressure piston-rods do 
Net area of high-pressure cylinders do 
Clearance of high-pressure piston do ... . 
Length of steam-port of nigh-pres.sure cylinder, 
inches 
Breadth of steam-port of high-pressure cylinder, 
inches 
Area of steam- port of high-pressure cylinder, 
inches 
Length of exhaust-port of high-pres-sure cylinder, 
inches 
Breadth of exliaust-port of high-pres.sure cylinder, 
incbe.s 
Area of exhaust-port of high pre.ssure cylinder, 
inches 
Number of ports in cut-off valve 
I.iength of ports in cut-off valve inches. . 
Breadth of iwrts incut-off valve do 
Aggregate area of cut-off valve-ports. .sq. inches.. 
Diameter of low-pressure cylinder inches.. 
Diameter of low-pressure piston-rod do 
Net area of each low-pressure cylinder do 
ijleafance of low-pressure pistons do 
Length of steam-porta of low-pressure cylinders, 
inches 
Breadth of two steam-ports of low-pressure cylin- 
ders inches. . 
Area of double steam-poit, of low-pressure cylin- 
ders iucbe.s . . 
Ratio of volume of displacement of low-pressure 
piston to that of high-pressure piston, per stroke. 
Length of pistons, on line of axis, at circumference, 
inches 
Thickness of metal in all cylinders inches. . 
Length of packing-rings on high-pressure pistons, 
inches 
I^ength of packing-rings on low-pressure pistons, 
inches 
Diameter of each (single-acting) air-pump plunger, 
inches 
Stroke of air-pump plungers inches. . 
Displacement of each air-pump plunger, per stroke, 
cubic inches 
Diameter of each feed-pump plunger inches, . 
Stroke of each feed-pump plunger do 
Displacement of each feea-pump plunger, i>er stroke 
cubic inches 
Diameter of steam cylinder of the circulating- 
pump inches.. 
Diameter of steam piston-rod of circulating-pump, 
inches 
Net area of steam piston of circulating-pump, cubic 
inches 
Diameter of water piston of circulating-pump, 
inches 
Diameter of water piston-rod of circulating-pump, 
inches 
Net area of water piston of circulating-pump. 
square inches 
Stroke of pistons of circulating-pump ...inches,. 
Ratio of area of steam piston to tliat of water piston 
('mtside diameter of condenser tubes inch.. 
Kxposed length of condenser tubes inches.. 
Comlensing surface of tubes. . . sq. feet. . 
Number of crank-shaft journals to ea<.'li engine. . . . 
Diameter of forward journal inches . . 
Diameter of middle journal do ... 
Diameter of after journal do — 
l.ength of forward journal do 
Length of middle journal do 
Len^h of after journal do 
Diameter of high-pressure crank-pins 
Length of high-pressure crank-pins 
Diameterof I6w-pre.ssure crank-pins 
Length of low-pressure crank-pins 
Diameter of bigh-pressure crosshead pins. . . , 
Length of high-pressure crosshead pins 
Diameter of low-pressur e crosshead pins. . . 
Length of low-pressure crosshead pins 
Diameterof line shafts (wrought iron) 
Length in vessel occupied by engines 
Breadth in vessel occupied by engines 
Height of engines above center line of shafts. 
2 
18 
13.5 
1.75 
23.625 
3.5 
47.25 
3 
13.5 
.875 
:i5.4375 
34 
3.5 
903.11 
30 
.5 
CO 
(5 
1 
4.5 
3.75 
10 
13.5 
2,814.ai 
4.5 
13.5 
214.7 
14 
10 
Ft. In. 
7i 
TWIN-SCREW ENGINES 
