MUSEUM OF COMPARATIVE ZOOLOGY. 173 
shoulders striking on the props P, P (Figs. IL, UL, V.) Should the 
wire part while reeling in, the cross-head, on flying up, would receive the 
blow against the upper shoulders, the latter striking against the cross- 
piece upon which rest the pulleys J, J. On the experimental machine 
a piece of rubber was fastened under the cross-piece to ease the shock. 
It was also our practice sometimes in reeling in to knot the two parts of 
the friction line somewhere near the bottom of the guides, leaving it 
still rove through the small pulley 0 (Figs. IL, VIL, VIII, IX.). Inthe 
latter case, if the wire parted, the friction line would prevent the cross- 
head striking the cross-piece. The tubes are graduated to 150 lbs., 
beyond which it is not safe to expose the wire in general use; it being 
presumed that in every very long length of wire there may be some 
weak spots. By the arrangement shown in the drawing, the cross-head 
pulley can be unshipped without removing the cross-head from between 
the guides, Should it be found that the wire has a tendency to fly off 
the cross-head pulley (something not likely to occur, excepting when 
reeling out slack wire to detach the sinker, after the latter is on bot- 
tom), a suggestion for preventing such an accident is shown in Figs. 
VIL, IX. 
The Swivel Pulley. — The object of this pulley, S (Figs. I, IL, V.), is 
to allow of the wire being reeled in while the vessel is steaming ahead. 
A steel sleeve fastened to the bed-board by bolts has a brass collar, to 
which is bolted the arm holding the pulley! In the positions shown in 
Figs. L, V., the pulley is ready for reeling in, and it can be swung later- 
ally to any desired angle. The score will always be in the same line 
with the score of the cross-head pulley. Before paying out the wire, — 
or before reeling-in, if it be not intended to steam ahead during the 
operation, — the arm T which holds the swivel pulley is released from 
the bolt U, when it will pivot on the bolt V. The pulley should then 
be lifted clear of the wire, and turned to one side and secured. 
The Scales (W, X, Fig. IV.). — They should be of the kind that have 
a long movement of the pointer for a slight extension of the springs in 
the scales. In the manner of bending the friction rope to them, as 
shown in the drawing, they would perhaps “slew” so as not to present 
the faces of the scales in the same plane. It would therefore be better 
to use braided rope ($ inch in diameter), and any seaman could bend on 
the line to suit the circumstances of the case. In paying out the wire 
the difference between the readings of the scales X and W will be the 
number of pounds of resistance applied to the reel by the friction rope. 
Wire and Stray Line. — The wire to be used is the sume as that rec- 
