4658 HYDROGRAPHIC MANUAL PaGE 396 



transferred to the sounding machine by power, and with experience and care the same 

 method can be used with piano wire. 



A conical-shaped wooden frame, 2)^ to 3 feet high, should be constructed, buUt 

 around an iron rod running through its center, on which it revolves as an axis. The 

 diameter of the base of the cone should be about 1 ji times the outside diameter of the 

 largest coil of wire to be used on it. With these dimensions a coil of piano wire should 

 rest about halfway between the apex and base of the cone, a coil of stranded wire 

 resting somewhat higher. 



Two wooden blocks with metal sockets should be built to serve as upper and lower 

 bearings for the iron rod. The lower block may be secured temporarily to the deck in 

 any convenient place and the upper block secured to a cross brace, so that the cone is 

 held securely between them in a vertical position, yet can revolve freely. A rope brake 

 is used, one end of which is secured and the other end held in the hand of an operator, 

 with about a three-quarter turn around the cone. 



The wire is led off the cone downwards and under a horizontal bar of wood, thence 

 upward over another similar bar at least 5 feet above the deck, thence horizontally for a 

 distance of about 10 feet to a sheave directly over the sounding machine, and onto the 

 reel. A sliding weight is placed on the wire between the higher of the two bars and the 

 sheave. This weight must be kept from sliding toward the sheave by a light cord 

 secured in the direction of the cone. The purpose of the sliding weight is to take up the 

 slack in the wire between the bar and the sheave at all times, otherwise piano wire will 

 surely kink sooner or later. This slack in the wire is also a safety factor, which gives 

 the operator of the reel time to stop it, if the wire jams at the cone. 



The sounding machine is started slowly either by hand or power. The men at the 

 machine and the rope brake watch the sliding weight constantly and are guided by its 

 position. The machine should be run at constant speed and any variations in tension 

 counteracted by the use of the rope brake. The brake is applied whenever the sliding 

 weight begins to fall, and slacked as it rises. Some experience and constant attention 

 are required, especially if the machine is to be run by power. The man at the machine 

 must be ready to stop it instantly if the sliding weight rises quickly, for this may indi- 

 cate that the wire is jammed at the cone and, if so, the wire will be parted if the machine 

 is not stopped. 



It is immaterial which end of a coil of wire is led to the machine, so long as the end 

 is clear. Soon after starting, the wire appears to come from the inside of the coil and 

 will continue to appear so until the entire coil is on the drum. 



A supply of wire may be carried on a storage reel, from which it can be transferred 

 to the sounding machine by power in a much shorter time than is required to rig and 

 use the cone for a new coil of wire. 



4658. Care of Sounding W ire 



Even galvanized sounding wire is likely to rust, unless properly cared for. At the 

 end of a field season, or at any other time when the wii'e is not to be used in the near 

 future, it should be run off the sounding machine I'eel, and thoroughly dried and oiled 

 when replaced. The surface of the reel, and any part which comes in contact with the 

 wire, should be well dried and freely coated with mineral grease, before rewinding the 

 wire. The reel of wire should be well wrapped with oil-soaked cloths. 



When in use, and especially after the last sounding of each day, the wire should 

 be run through a piece of well-greased canvas as it is reeled in. A brush dipped in 



