346 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The gypsy head, by which the wire rope is wound, is curved, ami the roiie comes 
in, consequently, on a vaiying diameter; as the mean velocity of the wire is less than 
that due to velocity of the center line of the wire wrapped on the smallest diameter 
of the head, it is evident there is a slip. The tendency of the rope, winding on the 
head, is to coil into a helix, but the inclination of the surface causes the wire to surge 
toward the ceutral part of tlie head, with some jar, slipping back at the same time. 
The loss of power due to this slip, iilus the power required to overcome the stiffness 
of the rope in bending it on the head, will be found by taking the difference between 
the net power applied to the revolution of the gypsy head and the iiower indicated 
by the dynamometer. 
The diameter of the smallest part of the gypsy head is 22|f inches, and the diam- 
eter of the wire rope is three-eighths of an inch; consequently the velocity of the rope, 
per revolution of the head, supposing there were no slip nor creeping, should 
/'22J-^ 4- a X 
be 7T ( ^ )=6.104 ieet,^ 
but fi'om the reading of the register it is only 5.924 feet. 
The following record is from the mean of a number of observations : 
Velocity of the rope indicated by the register, in feet per minute 148. 600 
Velocity of the rope due to the smallest diameter of the gypsy head 153. 100 
Tension on the wire, in iiounds, indicated by the dynamometer 2, 737. 5 
Revolutions of the gypsy head per minute 25. 083 
Eevolntions of the engine per minute 107. 500 
Indicated horsei>ower developed by the engine 15. 563 
Iudicat(Ml horsepower required to work the engine 1. 453 
Horsepower absorbed by the friction of the load 1. 167 
Net horsepower applied to the tension on the rope 12. 943 
Horsepower accounted for l>y the dynamometer 12. 327 
Horsepower absorbed by slipping and bending of the roiie on gypsy head. . . 616 
The 15.503 horsepower iudieated by the engine is divided as follows: 
Per cent. 
For pulling in the rope 79. 207 
For working the engines 9.335 
For overcondng the friction of the load 7. 500 
For overcoming the slip and bending of the rope 3. 958 
REELING ENGINE. 
100. 000 
The reeling engine was built by Copeland & Bacon, of New York, and is of the 
same character of design as the dredging engine. Its object is to stow the wire roiie 
and to keep a limited tension on that rope when in motion. It is essentially a 
wrought-iron, built-up drum mounted on a horizontal axis driven by a double- 
cylinder half-trunk steam engine through the intervention of toothed gearing and a 
friction clutch. It has a friction brake to regulate the paying out. 
It is provided with a traveliug guide, mounted in front of the drum, for guiding 
the rope smoothly and uniformly upon it. The guide is actuated by a double screw, 
with equal right and left ])itches, similar to that employed on the distributing roller 
of the Adams printing press. This screw reverses the direction of the guide when it 
reaches the end of the thread, aud the pitch of that thread is equal to the diameter of 
the rope. It is geared to the drum by toothed gears of equal pitch diameters, one 
of which has a clutch coupling for disengaging. When paying out rope, the guide is 
*Tbis is on tlie assiini]itioii that tlie rope traveks on a ratlins due to that of the gyi>8y bead plus its 
owu radius, wliicli has beeu jtroved by the passage of the same wire over our register sheave. 
