Isthmian offices. PLATE 112. Office force of chairman and chief engineer, assistant chief engineer, and assistant to the chief engineer. 113. First division of chief engineer's office. 114. Central division. 115. Atlantic division. 116. Pacific division. 117. Secretary of the commission. 118. Mechanical division. 119. Chief quartermaster. 121. Civil administration. 122. Chief sanitary officer. 123. Disbursing officer, examiner of accounts, and department of law. 124. Panama Railroad Co., including New York offices. 125. Panama Railroad Co., relocated line. Washington office. 126. General purchasing officer. ANNUAL REPORT OF THE ISTHMIAN CANAL COMMISSION. ISTHMIAN CANAL COMMISSION, OFFICE OF THE CHAIRMAN, Culebra, Canal Zone, September 10, 1912. SIR: I have the honor to submit the annual report for the Isthmian Canal Commisison for the fiscal year ended June 30, 1912. ORGANIZATION. When it was determined to fortify the canal it was recommended that the construction be done by the Isthmian Canal Commission, utilizing its forces and such plant as could be spared from other work under its charge, as this would result in economy in cost and avoid the friction liable to occur if two independent organizations were carrying on work in the same locality. It was proposed at the same time, in order that the completed work might embody the latest improvements in battery construction, that the plans be prepared by the Chief of Engineers, United States Army, subject to the approval of the Panama Fortification Board, and the batteries and accessories built in accordance therewith. This recommendation received the approval of the authorities at Washington. Funds for commencing the work were provided by the sundry civil act of March 4, 1911, and work was begun August 7, 1911, under the division engineer of the Pacific division and continued in his charge until January 1, 1912, when an additional division was established in the office of the chief engineer, which took over the construction of the fortifications. The third division of the chief engineer's office, which formerly had charge of general surveys not embraced within the limits of any construction division, together with the meteorological and hydrographic work, was abolished on January 24, 1912, when the general survey work was practically completed. What remained of this, together with the collection of meteorological and hydrographic data, was consolidated with the second division of the chief engineer's office. The locks and their various appurtenances were designed by and under the direction of Col. Hodges, and, as noted in the last annual 61012-12-1 1 report, the erection of the gates, valves, fender chains, and emergency dams, as well as the machinery for operating the lock accessories, were also placed under the division of which he has charge. Active field operations for erecting the machinery were undertaken in September, 1911, and an organization was arranged to handle the work. In the same month, under the same division, field forces were organized to undertake the erection of the range lights and other construction work required in connection with the aids to navigation. Last year recommendations were submitted looking toward the construction of a dry dock, coaling station, and terminal facilities, and, as these seemed to be favorably considered by the congressional committees visiting the Isthmus, a designing force was organized under Mr. Rousseau for preparing the necessary plans for the dry dock, coaling stations, and machine shops. Rather than tie up some of the French dredges on the Pacific side which could no longer work to advantage, in October, 1911, they were put at work dredging the area which was to form the basin between the canal and the proposed terminals. In June, 1912, when pending legislation indicated that the various facilities indicated would be authorized, and as time is an essential element, a force was organized under the division engineer, Pacific division, and work was begun by excavating to the north and west of Sosa Hill to enable the moving of the Panama Railroad tracks, so that work can be commenced on the machine shops and terminals. The design of the wharfs in connection with the terminals was assigned to Mr. Williamson. Continuing the principle of concentration which was adopted in 1908, the shops which formerly had been under the division engineer of the Atlantic division at Gatun were transferred temporarily to the mechanical division on April 4, 1911, and have been so continued since that date. Effective July 1, 1912, the shops at Empire for the repair of steam shovels, and previously in charge of the central division, were transferred to the mechanical division. With the exceptions noted, the organization of the forces on the Isthmus was continued practically as outlined in previous annual reports. CONSTRUCTION AND ENGINEERING. FIRST DIVISION. The first division of the office of the chief engineer, under Col. H. F. Hodges, United States Army, assistant chief engineer, continued in charge of the design of the locks, dams, regulating works, and accessories; the design and construction of aids to navigation: the inspection of the manufacture and erection, under contract or otherwise, of the lock gates, operating machinery, gates and valves, emergency dams and fender chains, and of the placing of such concrete in the locks as was omitted until the installation of the machinery. During the fiscal year the general plans for the lower portion of the lower locks at Gatun and Miraflores were completed and approved, as well as the plans for the south middle approach wall at Miraflores and for the uncompleted portion of the south middle approach wall at Pedro Miguel, which was changed from the solid type already built to the reenforced cellular type for the remainder. In addition, all the drawings required for decking over various machinery chambers in the lock walls, snubbing posts, and spring buffers were prepared, so that all the detailed plans for the locks are completed and approved. Chambers were prepared for the rising stem gate valves by lining up the fixed irons, and 12 completed at Gatun and 2 at Pedro Miguel during the year; at Gatun 12 valves were placed in position. In addition, 6 bulkhead gates were placed in the side-wall intakes and 6 in the center-wall intakes at Gatun. Three rising stem gate valves and 1 cylindrical valve were placed in the Gatun spillway. The cylindrical valves were placed in all the locks during construction and all of them are in position. To determine the probable leakage around the rising stem valves, also the force required to start the valve and to maintain the motion, a test was made on a set of two valves which were installed in the upper valve chamber of the west side culvert at Gatun. The entrance to the culvert was closed by a water-tight bulkhead, and the culvert between the bulkhead and the valves, with the well above the valves to the top of the wall, was filled with water. By this arrangement there was a greater head against the valves than will obtain when the lock is pumped dry for examination, and considerably greater than the usual operating head. Under a 79-foot head that resulted the combined leakage of both valves was 1.82 cubic feet per second, while the combined friction resulting from the contact of the side seals of the gate, as well as the action of the roller trains, averaged 21,170 pounds for each valve. It had been assumed at 31,750 pounds in the design of the machinery which was intended to exert a lifting force of 60,000 pounds, including all friction and the weight of the valve and its accessories. It is probable that both the friction and the leakage will be reduced in subsequent valves, as certain improvements in detail and workmanship are found in those of later construction. One of the cylindrical valves in the locks at Gatun was tested for leakage from the exterior by constructing a bulkhead across the entrance to the valve chamber, which was then filled with water. When the head reached 60 feet the leakage was found to vary from a quantity too small to measure to about 0.25 of a cubic foot per second. The average was about what was to be expected from the tests made at Pedro Miguel and described in the last annual report. Examination indicated that the leather seal or gasket was sufficiently rigid to hold up the movable portion of the valve and prevent its seating properly. The segments which clamped the leather seal were removed and the edge beveled slightly to allow an easier bending of the gasket. After this was done the leakage was found by measurement to be about 0.015 of a cubic foot per second, or about one-tenth of that previously measured. The segments for all the valves are being beveled in the manner indicated as advisable by this experiment. The two rising-stem valve machines furnished under contract were tested at the works of the manufacturer and found to be satisfactory, after which the commission exercised its option and contract was entered into December 5, 1911, for furnishing all parts for 114 rising-stem gate-valve machines without motors. After successful test of the first two cylindrical valve machines at the works of the manufacturer, contract was awarded, on October 25, 1911, for 118 additional cylindrical valve machines without motors and 12 auxiliary culvert valve machines without motors. Up to June 30, 1912, a total of 21 rising-stem valve machines (except valve stems and thrust screws), 34 cylindrical valve machines, and 3 auxiliary culvert valve machines were received. Delays in shipment occurred, caused by the strike of stevedores at Baltimore, the point of ship ment. Owing to the peculiar climatic conditions on the Isthmus, involving tropical heat and extreme humidity, and the deteriorating effect of these conditions on the insulation of electrical machinery, it was necessary to investigate thoroughly the different kinds of insulation available for use on the lock machinery. To accomplish this, 16 sample motors in all were purchased, 2 from each company offering bids for the motors required. Eight of these were sent to the machine contractors for operating tests on the valve machines, and the other 8 were shipped direct to the Isthmus, where they were subjected to the extreme conditions specified in the specifications accompanying the invitation for bids, in order to test the insulation. They were first placed in a storehouse at Gatun and exposed to the ordinary conditions of climate for a period of about two months, during which time the condition of the insulation was determined periodically by inspection and tests. In order to expedite the action of the heat and humidity they were subjected to a steam test, in which the extremes of temperature and humidity mentioned might be reproduced. In order that the conditions of all motors might be |