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August, 1916 At the close of the test, the oiler was let down. The brickwork ap- peared to be in a very good condi- tion; the bottom appeared to be somewhat uneven, indicating that the magnesia under the bricks was disin- tegrating to some extent. During Feb. 8, the feed pump was overhauled. Additional asbestos mill- board was placed behind the metal side casing, and the brickwork, espe- cially that on the left side of the boiler, was repaired. Test No. 3 Approximate rate, 3,100 pounds of oil per hour. Fires were started at t50° p. .m,, Heb. 9, 1916... Data for the test were taken from 1:30 p. m. Test ended at 6:30 p. m. On account of insufficient time to get the boiler warmed up to proper condition, it was decided to use data for four hours, from 2:30 p. m. to 6:30 p. m. Seven burners were used. The burn- ers used had 3/32-inch tips and 3/64- inch plugs. Two oil pumps, two feed pumps and both feed heaters were used. Owing to the lightness of the oil, difficulty in forcing a sufficient amount through the burners was ex- perienced when the oil was heated. The oil was therefore not heated after the first hour. With cold oil the required amount of oil was burned. There was no_ observable smoke during the entire run. The left side of the casing became red-hot during the test, indicating that there FIG. 3—PORTION FIG, 2—SECTIONAL VIEW OF BOILER OF FRONT THE MARINE REVIEW 269 anni, a FIG. 4—SECTION THROUGH WROUGHT STEEL BOILER HEADER SHOWING METHOD OF STAYING - TUBE AND HANDHOLE SHEETS is insufficient insulation in the casing as the boiler is usually built. The boiler steamed freely under all the tests. The circulation is evidently satisfactory. Small propellers were placed in two of the intermediate 4-inch tubes, with a rod _ running through the hand-hole. The move- ments of these rods indicates a down- flow in the 4-inch tube: at all rates ‘of steaming. Character of Circulation After the regular test the Charles Ward Engineering Works, at the sug- gestion of the board, installed pro- pellers in several of the 2-inch tubes, as shown in Fig. 2, to ascertain the character of the circulation. No. 2 began to revolve about five minutes after the fires were started; the di- rection of rotation showed down-flow in these tubes. No. 1_ hesitated slightly, showing some inclination to turn left-handed, which was probably due to suction caused by the down- flowing water from No. 2. This condition changed before steam was raised, and No. 1 began to revolve in the opposite direction, showing that the water was flowing up the lower bank of 2-inch tubes. Nos. 3 and 4 began to revolve left-handed in about 10 minutes after the fires were lighted, the speed increasing until they were running like windmills, so fast that the revolutions could not be counted; the direction of rotation showed down-flow: in these tubes. No. 4 remained stationary until there was abou 50 pounds of steam on the boiler, and then it commenced to revolve in a left-handed direction, indicating that. as soon as the water level raised on the high side of the tubes, due to the steam-making con- dition, there was a down-flow through the 2-inch tube mentioned. From these experiments it may be _ in-