Seas To Be Linked By Canal Oct. 10.

New York Times 100 years ago today, July 21, 1913:
Goethals Fixes That Date for Dynamiting Gamboa Dike, Last Panama Barrier.
WILL LET LAKE FLOOD CUT
Big Wall Doomed to Fall Keeps Gatun Waters Out of Culebra During Excavation.
    PANAMA, July 20.— Col. G. W. Goethals, Chief Engineer in charge of the construction of the Panama Canal, has notified Lieut. Col. David DuB. Gaillard, Chief of the Central Division of the canal, that steam shovel work in the Culebra Cut section hereafter will be conducted on the assumption that Gamboa Dike will be dynamited on Oct. 10. Although it had been announced that this dynamiting would take place after Oct. 1, this is the first time the actual date has been named.
    The destruction of the dike will permit Gatun Lake to flood the cut, thereby practically connecting the Atlantic and Pacific, although actual navigation of the canal probably will not be attempted for some time thereafter. Excavation in the cut henceforth will be confined mainly to removing the remaining hard rock sections between Cucaracha Slide and Empire, a distance of a mile.

Carries Out Well-Laid Plans.
Special to The New York Times.
    WASHINGTON, July 20.— Col. Goethals's order that shovel work in Culebra Cut proceed on the assumption that Gamboa dike will be dynamited on Oct. 10 means that the Government's plan to flood the Culebra Cut with water will be consummated on time.
    Gamboa Dike is a great artificial embankment at the northern end of the Culebra Cut. It was erected to prevent the waters of the Chagres River and Gatun Lake, which is now being created artificially by impounding the waters of the Chagres River, from flowing into the cut at Culebra in its excavation.
    The canal prism being 500 feet wide at the base, the great dike at Gamboa is nearly 100 feet long. This dike is 48.2 feet high, with sides sloping toward the canal prism and also toward the Gatun Lake, the dike being 183 feet wide at the base and 65 feet wide at the top.
    Gatun Lake came into existence on April 25, 1910, when the west diversion dam at Gatun was closed and the flow from the Chagres and Trinidad Rivers was forced through the artificially constructed spillway channel.
    Since then the waters in the lake have risen gradually, and last Fall the rising of the lake caused the waters of the Chagres River to back up against the great dike at Gamboa, protecting Culebra Cut. For several months the water in the Chagres River, backed up against this Gamboa Dike has been higher than the bottom of the finished part of Culebra Cut.
    Since 10:40 o'clock of the morning of June 27 last the gate of the sluices through the ogee of the Gatun spillway has been closed. At that time the surface of the water in Gatun Lake was 48.3 feet above sea level, having been maintained at that level from Jan. 1, 1913, when the sluice gates were opened. The spillway has been completed, and it is not the intention of Col. Goethals to permit the sluice gates to be opened again.

Lake on Its Last Rise.
    This means that the lake is on its final rise to the operating level. Under conditions of normal runoff of the water from the Chagres and other streams which are pouring their flow into Gatun Lake, where the water is being held, it is thought Gatun Lake will reach its final level of 83 feet above the level of the sea about Dec. 1, 1913. This depends on the rate of flow of water into the lake, and the estimate is based on measurements recorded over the watershed for the last twenty-three years.
    Col. Goethals, according to the latest report received in Washington, estimates that the level of water in Gatun Lake should rise to 71 feet above sea level, the elevation of the railroad at Gorgona, about Oct. 1. At that height the lake would give a twenty-one-foot channel through Culebra Cut. The town of Gorgona would be covered with water and wiped off the map.
    The top of the dike at Gamboa protecting Culebra Cut from flooding through its north end is 78.2 feet above sea level, but it is thought the water will be let into Culebra Cut before the lake reaches that elevation, which it may do about Nov. 1.
    The waters now being impounded in Gatun Lake drain a basin comprising 1,320 square miles. When the surface of water in the lake rises to 85 feet, the level at which it will be maintained for the operation of the canal, the lake will have an area of 164 square miles. It will be the largest artificially created lake in the world. There will be 183,000,000,000 cubic feet of water in the lake. When the level of the lake is 85 feet above sea level there will be a depth of 45 feet in Culebra Cut.
    When Gamboa Dike is dynamited out of existence and water is admitted into Culebra Cut from both sides great ladder-like dredges will be brought into the cut to work at the foot of any slides which continue to develop in the cut, in addition to removing the remainder of the dike and cleaning out about 150,000 cubic yards of silting in the competed channel between Gamboa and Mamei. About 4,000,000 cubic yards of earth must be excavated in Culebra Cut before the removal of Gamboa Dike on Oct. 10. To date the excavation in Culebra Cut has amounted to about 105,000,000 cubic yards.

PANAMA'S POWER SYSTEM.
Canal Zone's Electric Plant Will Be Most Complete in the World.
    The issue of The Canal Record, the official weekly bulletin of the Isthmian Canal Commission, which reached New York yesterday, contains a description of the plans for the permanent electrical system for the Canal Zone, the installation of which The Record says has just been begun. When finished there will be no more complete electrical plant in existence than that of the Panama Canal Zone. The Record says:
    Construction work has been begun upon the permanent electrical transmission line across the Isthmus. A few foundations for the track-span bridges have been placed at New Culebra siding, on the Gold Hill relocation of the Panama Railroad, and first shipments of steel for the bridges have arrived from the United States. A shed is being constructed in the abandoned borrow pit just east of Gatun Locks for the assembling of the bridges.
    The transmission line is fundamentally to transmit electrical energy from a source of generation at Gatun to load centres at Miraflores, Balboa, and Cristobal. The system is simple and straightforward. At the Gatun spillway a portion of the lake water will be passed through turbines to generate electrical energy.
    The energy, generated at 2,200 volts, 25 cycles, three-phase, will be carried along the east wing of Gatun Dam by heavy cables in duplicate underground duct lines, and through tunnels under the locks, into a transformer substation, situated on the east side of the locks. The duct lines are in duplicate, to insure maximum safeguard against damage in event of a burn-out of a cable in one or the other of the lines, and are to be laid approximately 600 feet apart.
    At the Gatun sub-station, which will be situated on the hill where the present office building of the Atlantic division of the canal stands, the electrical energy will be transformed from 2,200 to 44,000 volts by means of step-up transformers. In addition to the three 2,000-kilowatt transformers, the plant will have the necessary auxiliary appurtenances, while two high extension lines will emerge from the sub-station and tap duplicate transmission lines. The Canal Record, continuing its description, says:

Line Will Cross Isthmus.
    The transmission line will run from Cristobal to Balboa, completely across the Isthmus permitting distribution of energy both ways from Gatun. The line is to parallel the right of way of the Panama Railroad for its entire length. At Cristobal and Balboa will be terminal sub-stations similar to the Gatun sub-station. The terminal sub-stations will receive the energy at 44,000 volts, less the voltage drop in the line, and step-down transformers will convert the pressure to 2,200 volts, which will be the distributing voltage for all circuits. At Miraflores, a sub-station will be installed for supplying energy for the motors and lamps of Pedro Miguel and Miraflores Locks.
    If electricity is required along the line, the transmission lines will be tapped by outdoor type of transformer sub-station equipment. This will probably be done at Caimito, to supply electricity to the high power radio station; at Monte Lirio, to supply power to the bascule bridge, and at any permanent town or military reservation which demands electric lights and power.
    At Miraflores the present steam turbogenerators will be tied into the permanent electrical system through 2,200-volt tie-lines extending to the Miraflores substation. This steam station will serve as a reserve in the event the hydroelectric station at Gatun should break down. In emergency, energy from Miraflores will be transmitted back to Gatun, and to the terminal substations at Cristobal and Balboa, insuring a continuity of service on the system at all times. By paralleling the Panama Railroad the construction of the vast electrical system has been greatly simplified, it being possible to bring material to within a few feet of the point of actual construction. The side bracket suspension of the conductors separates the duplicate lines so that a burn-out in one conductor will in no way affect any of the others. The Record continues:

Great Copper Cables.
    A few details of construction are worthy of note. The No. 00 copper conductors are 7-strand pure copper cables, totaling 1,500,000 feet in length. The individual strands are manufactured without either a soldered or a welded joint. Splices in the cable will be made with soft copper sleeves. The conductors are suspended at the insulators from monel metal fittings, which are bushed with a copper sleeve. Thus, in the entire length of line, there will be no point where the copper strands are in intimate contact with a second metal; this prevents the introduction of an electric couple and consequent electrolytic deterioration.
    At each track-span bridge the ground wire will be clamped to the tower, and a positive T-connection through a copper wire will be made to ground plates buried in the earth. These ground plates are being manufactured from old scrap copper and cable which have accumulated at the Empire storehouse. By frequently grounding the ground wires it is expected that line trouble and substation burnouts caused by lightning will be reduced to a minimum. Five hundred thousand feet of copper-clad wire are required for the two ground wires. The insulators, which will support the conductors, are of two types, suspension and strain, each assembled of three porcelain disks, ten inches in diameter. Joined by monel metal fittings. This metal is used on account of its unusual strength and its ability to resist corrosion; galvanized fittings which are customarily used in the united States and abroad are considered practically worthless in the Isthmian humidity.
    The new system when finished, which will be about the time the canal is opened to the traffic of the world, will, in addition to the lighting of the canal itself, supply power to the public works of the cities and towns within the canal zone, the wireless stations, the naval and army depots and water works of the entire zone.