tures for troops in the vicinity of the various canal structures which they are guarding. Additions and alterations were made to buildings 6, 7, and 9, Balboa shops, alterations to Balboa and Cristobal mess houses, and Young Mens' Christian Association buildings were constructed at Paraiso and Cristobal. Details showing the total and unit cost of the buildings completed during the year are contained in the report of the building division, Appendix A. LOCKS OPERATION. At Gatun there were 1,741 commercial and 160 noncommercial lockages, and 1,909 commercial vessels were passed through during the year; at Pedro Miguel there were 1,797 commercial, 271 noncommercial lockages, and 1,938 commercial vessels were passed; at Miraflores there were 1,792 commercial, 233 noncommercial lockages, and 1,930 commercial vessels were passed. The ships passed exceeded the number of lockages because it is the practice to lock two ships through simultaneously when they arrive at the locks within a short time interval and their combined length does not exceed 720 feet. There were no delays due to machinery failures in any of the lock operations and there were no cases of serious damage to ships while in the locks. The most frequent minor damage is the breaking of the ships' chocks, due in almost every instance to their defective construction and insufficient strength to take the strain of the tow line. The maintenance work at the locks has consisted in the systematic inspection and overhauling of all the operating machinery and towing machines, minor changes in small details as improvements were developed by use, painting of gates and other exposed steel surfaces, repairs to the floating caisson, the renewal of timber fenders on the wing and approach wall, and the application of bitumastic solution and enamel to the valves and submerged portions of the lock gates. At Gatun experimental use was made of a patented machine for applying a protective coating of zinc on steel and other metallic submerged surfaces, with the idea of preventing the voltaic action that causes corrosion. One of the rising stem valves, with the roller train rods, guide bearings, the valve stem, and all bolt heads and nuts were thoroughly cleaned and sand blasted, and a coating of zinc applied. A section of the downstream side of one of the gates below sea level was similarly treated. Since the work was done the lock has not been unwatered, and no information is as yet available as to the success of the experiment. The expedient of using greenheart lumber to replace the babbitt metal valve seats and lignum-vitæ side seals in place of machinery steel at Miraflores, as described in last year's report, has been only partially successful in checking the corrosive action experienced. The bitumastic enamel was successful as a protective coating for the valve surfaces, so far as can be judged during the short time that has elapsed since it was applied. Maintenance work has been done by the Bitumastic Enamels Company under their guaranty to maintain the coating applied by them to the lock gates at Gatun and Miraflores. At Gatun the surface so retouched on the gates of the upper and middle chambers has amounted to about one-third of the original surface covered. This work was evidently made necessary by the failure of the material to adhere to the steel surface of the gates, and this was probably due to lack of care in cleaning and drying the surfaces before applying the bitumastic. Where the bitumastic has adhered to the steel it has afforded satisfactory protection both against rust and on account of the insulating property of the material against corrosion due to voltaic action. At Pedro Miguel bitumastic solution and enamel purchased from the Navy Department has been applied to the gates by the lock forces. The cost of the work, including the materials, was much less than the contractor's price, but the maintenance of the protective coating for five years will have to be considered before an actual comparison of costs can be made. The unwatering of lock chambers for purposes of inspection, painting and repairs of valves, and the painting of gates has caused one side or the other of the double locks to be closed to traffic for periods, as follows: Gatun, 188 days; Pedro Miguel, 119 days; and Miraflores, 124 days. A few items of construction work were completed at the locks; among them is a dock landing for small boats at the northeast wing wall of the Gatun locks; mess buildings for gold and silver employees, repair pits for towing locomotives, and grading of backfills at the Pacific locks The work at the Gatun spillway consisted entirely of painting the spillway gates and bridge and the usual upkeep of the operating machinery. The installation of heavy steel plates on the baffle piers to prevent erosion was delayed, due to nonarrival of material, until too late to complete the work during the dry season. This work must of necessity be done in the dry season on account of the frequent opening of the spillway gates during the rainy season. At the Gatun dam a fill was made along the crest for a length of 550 feet west of the locks, in order to restore the section to full height. Earth excavated at the site of the addition to the hydroelectric station at the spillway was used in making the fill; the amount placed was 15,000 cubic yards. ELECTRICAL DIVISION. This division remained in the charge of Maj. William H. Rose, United States Army, until his relief from duty with the canal on June 1, 1917, when Maj. T. H. Dillon, United States Army, was ap pointed to succeed him. The hydroelectric generating station at Gatun, the reserve steam-driven electric-generating plant at Miraflores, the substations, transmission lines, and power-distributing systems throughout the canal were all satisfactorily maintained and operated. This division also continued to install, maintain, and operate the municipal and house lighting systems, the telephones and telegraphs, fire alarm, and the railway block signals and interlocking plants. The average monthly consumption of electricity generated for all purposes was 3,645,325 K. W. H., at a cost, including depreciation, of $0.0073 per K. W. H. consumed for power purposes, and $0.0134 for lighting purposes, the latter figure including maintenance of interior house wiring and lamp renewals. The new water wheels, referred to in last year's report, were installed at the Gatun spillway, resulting in an increased capacity from 6,000 K. W. to 8,640 K. W., at 80 per cent power factor. This work was completed December 19, 1916, at a cost of $16,377.91. Funds were provided for the installation of an additional unit and the extension of the station building to accommodate this unit and provide space for the future installation of two more units. This work was begun on January 1, 1917, and at the end of the year the concrete draft tubes and the foundations of the building extension were completed and the erection of penstocks 10 per cent completed. A contract was made on November 22, 1916, for the construction of the new generator unit, to be delivered on December 2, 1917. This generator will be a General Electric 66,000-volt, 3-phase, 25-cycle, 4,500 K. W., at 80 per cent power factor, mounted on a vertical shaft direct connected to a 6,750 H. P. turbine furnished by the Pelton Waterwheel Company. With the changes heretofore made in the three water wheels originally installed, this additional unit will increase the capacity of the Gatun station to 13,140 K. W., and the ultimate capacity provided for when the two additional units are installed will be 22,140 K. W. This will take care of about twice the present load and will make available a reserve of about 50 per cent above any increases in load now in contemplation. The work of installing in the Miraflores station the units from the dismantled steam-power plant at Gatun was completed on December 14, 1916. This installation increased the capacity of the Miraflores station to 7,200 K. W. The steady growth of the electric load on the canal has made necessary the intermittent operation of the Miraflores plant to carry the peak loads pending the increase in capacity of the Gatun hydroelectric station. As a reserve the Miraflores plant provides power for the Pacific locks and the lighting and power systems at the Pacific terminus of the canal at times of breakdown in the transmission lines or other interruptions of power from the Gatun plant. The principal additional loads carried during 1917 were: Balboa coaling plant, 1,267 K. W.; Balboa dry dock, 6,040 K. W.; air-compressor plant at Balboa, 1,600 K. W.; cold storage and ice plant, Balboa, 450 K. W.; and additional lights requiring 1,300 K. W. in the various municipal buildings, schools, and Army and canal quarters. To provide an adequate reserve at the Miraflores plant it will be necessary to increase its capacity so as to maintain it at about two-thirds the capacity of the Gatun plant. The necessity for increased electrical output has led to a consideration of the water consumption from Gatun Lake by the Gatun hydroelectric station and its effect on the level of Gatun Lake during the four months' dry season. The dry season of 1917 was abnormal in length and in deficiency of rainfall, and as the traffic through the canal was above the average and the consumption at the hydroelectric station increased, an opportunity was afforded to observe the fall in lake level under conditions of large consumption and smal] inflow of water. The results are discussed in the part of this report relating to meteorology and hydrography. It may be stated here, however, that it will be necessary, with a pronounced increase in canal traffic, to operate the hydroelectric station at less than its ultimate capacity during dry seasons and to supply the deficiency in electric power by the operation of the Miraflores plant during the corresponding periods. There was a large increase in telephone service during the year. On June 30, 1916, 1,878 telephones were in use, and on June 30, 1917, 2,154. The average number of telephone calls per day was 21,042. To care for the increase in telephone business plans are developing for a new exchange at Cristobal and the installation of additional cable for trans-isthmian service. The construction work of the division included the laying of 185,000 feet of underground cable and the installation of lighting systems in 86 Army buildings, 45 Panama Railroad buildings, and 991 apartments for canal employees. For further details attention is invited to Appendix A. MUNICIPAL ENGINEERING DIVISION. This division continued under the immediate charge of Mr. D. E. Wright, as municipal engineer, reporting to the engineer of maintenance. The work of the division consisted of the maintenance and repair of municipal improvements in the Canal Zone and in the cities of Panama and Colon, the care and maintenance of the water reservoirs, and the maintenance and operation of the pumping stations and water filtration plants. In addition to the maintenance work the division performed all road and municipal construction work for all new town sites for the canal, and similar work in the Army posts, Fort Grant, Fort Sherman, Fort Randolph, and Fort De Lesseps. The reservoirs and pumping plant on the west side of the canal, for the service of the military posts at Las Cascadas, Empire, and Culebra, were maintained and operated. At the Mount Hope pumping station the average number of gallons pumped a month was 119,169,500; at Agua Clara, 27,084,750; at Gamboa, 284,661,833; at Miraflores, 30,162,500; at Balboa, 205,171,250; and at Paraiso, 6,220,166. The average division cost for water delivered in the various districts per 1,000 gallons during the year was as follows: Cristobal, $0.06; Gatun, $0.11; Gamboa, $0.34; Paraiso, $0.07; Pedro Miguel, $0.07; Miraflores, $0.06; and Balboa-Ancon, $0.06. These figures include the costs of filtration and purification at the filtration plants at Mount Hope and at Miraflores. At Cristobal 47,257,000 gallons and at Balboa 14,558,000 gallons were sold to ships during the year. The municipal maintenance work performed in the cities of Panama and Colon, at a total cost of $152,289.89, was repaid to the municipal division from water rentals, in accordance with the terms of our agreement with Panama. In the city of Panama the average daily consumption of water for the year was 2,398,250 gallons, and in Colon 1,626,695 gallons. The principal items of construction by the municipal division for The Panama Canal consisted of the grading of grounds and the installation of water and sewer lines, streets, and sidewalks in the new addition to the town at Balboa, making fill and grading grounds and constructing water and sewer systems, streets, and sidewalks in the new town of Cristobal, and the construction of connecting roads in outlying districts. For those purposes the expenditures were $488,948.81. For the Army, $530,912.70 were expended in grading, installing water and sewer systems, and constructing streets and sidewalks at Fort Grant, Fort Sherman, and Fort Randolph, the construction of a concrete road from Fort Randolph to Mount Hope, from Fort Grant to Balboa, and the construction of roads, streets, water and sewer lines for the new Ordnance Depot at Corozal, and repairs to roads and streets in the camps at Culebra, Empire, Las Cascadas, and Quarry Heights. For the Panama Railroad there were constructed the G Street storm sewer in Colon, the railroad's share of the Curundu River storm sewer, the roads at the Cristobal piers, water lines for cattle pastures, roads to a number of the plantations, and improvements to pavements in the vicinity of the passenger station of Panama City. The cost of the work performed at the expense of the railroad was $126,849.40. Work done for outsiders, for which deposits were made to cover the cost, included the making of private water taps, the construction of short sections of road, and repairs to the tramway company's right of way in Panama City and to the streets in Panama and Colon that were opened up for the |