172 BULLExm or the 



posed of three separate pulleys, C, D, and F, — the score E for the 

 •wire ; the score C for a connecting rubber or rope baud 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. I., 

 11., HI., IV., v.), containing the spiral springs G, G (Fig. III., 31 

 inches long, 2| inches outside diameter, 4 feet movement for 150 lbs. 

 strain directly applied), connected with movable cross-head H (Figs. 

 IL, VII., VIII., IX.) by means of the chain (or wire rope) /, / (Figs. 

 L, IL, III.), which pass over the pulleys J, J (Figs. I., IL, XII.). 

 Each tube is in three sections, the upper section being 2| inches 

 inside diameter, and ^ inch in thickness; and the lower sections 

 2 1 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 //, con- 

 taining the pulley L (Figs. I., VII., VIIL, IX.), moves on the guides 

 M, M (Figs. IL, III., v., XL), which are screwed to the tubes. The 

 pulley L is rigidly attached to its axle by a key. To the axle is attached 

 an odometer, i\" (Fig. IL). The pulley is exactly one yard (| 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 

 pulley and cross-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 ; also, 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 16| lbs., 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, (Figs. IT., VII., VIIL) are shoulders to guard against 

 the bending of tl»c cross-head in case of parting the chains 7, /, or of part- 

 ing the wire. Should the chains part, the cross-head would fall, the lower 



