172 BULLETIN OF THE 
posed of three separate pulleys, €, D, and E, — the score E for the 
wire ; the score 0 for a connecting rubber or rope band with the friction 
score of the reel, if desired; and the score D for an endless rope band 
connecting with the hoisting-engine. 
The Accumulator is composed of the tubes F, F, F, and C (Figs. Ji, 
IL, TIL, IV., V.) containing the spiral springs G, G (Fig. IIL, 31 
inches long, 24 inches outside diameter, 4 fect movement for 150 lbs. 
strain directly applied), connected with movable cross-head H (Figs. 
IL, VIL, VIIL, IX.) by means of the chain (or wire rope) J, Z (Figs. 
I., IL, IIL), which pass over the pulleys J, J (Figs. I, IL, XIL). 
Fach tube is in three sections, the upper section being 24 inches 
inside diameter, and } inch in thickness; and the lower sections 
24 inches inside diameter, and } inch thick. The tubes are hinged at 
K, K (Figs. I., IL, III., IV.), so that the upper sections may be lowered 
for convenient stowage. They are graduated for the number of pounds 
pull on the wire, the upper arm of the cross-head being the index. "The 
lower section of each tube unscrews for stowage. The cross-head J, con- 
taining the pulley L (Figs. L, VIL, VIIL, IX.), moves on the guides 
M, M (Figs. II., II., V., XL), which are screwed to tho tubes. "The 
pulley Z is rigidly attached to its axle by a key. To the axle is attached 
an odometer, N (Fig. IL). The pulley is exactly one yard (4 fathom) 
in circumference on the face, less the allowance for thickness of wire. 
One half the number of revolutions shown by the odometer will there- 
fore give the number of fathoms of wire payed out or reeled in. Both 
head should be made as light as strength will admit 
(gum metal would probably be the best material for them), since the 
momentum which they acquire during the plunges of the vessel must 
be overcome before the cross-head can respond to the reactionary im- 
pulse of the springs ; algo, because it is desirable that very little of the 
extension of the springs should be taken up by the weight of the cross- 
head and pulley. As much as possible of this extension should be 
reserved for sustaining the pull of the wire in reeling in. Again, it is 
probable that a very heavy cross-head needs to be counterbalanced. 
The combined weight of the springs is 164 Ibs., and if the weight of the 
cross-head and pulley approximates to that amount, the weight of the 
springs will act as a counterbalance. There will be very little lateral 
strain on the cross-head other than that due to its own weight while the 
ship is heeled. 0, O (Figs. IL, VII., VIII.) are shoulders to guard against 
the bending of the cross-head in case of parting the chains J, Z, or of part- 
Should the chains part, the cross-head would fall, the lower 
pulley and cross- 
ing the wire. 
