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270 EEG, ferred that the flow is upward through all the 2-inch tubes below the middle baffle, and downward through all the 2-inch tubes in the upper portion of the boiler, the velocity being quite rapid, for, as stated, the propellers were revolving in the neighborhood of 200 revolutions per minute or more. The high velocity of the propellers in the small tubes is due to the fact that the shafts were of very small diameter and consequently there was very little friction. To establish the volume of water flowing down through the 4-inch tube, one of the propellers was removed and installed in a short piece of pipe, this being connected to the city water main and the propeller operated un- der a pressure of about 40 pounds, the discharge being throttled until the propeller made approximately the same number of revolutions as it did in the boiler. Readings from the water meter over a period of five min- utes showed that there was about 50 gallons per minute passing through this tube. This, however, is only an indication of the amount of water flowing through the 4-inch tubes, as the friction on the propeller was very much greater under the higher pres- sure conditions existing in the boiler. The foregoing results are very in- teresting, and are believed to throw a’new light upon the problem of cir- culation in boilers of this general type of construction. They also in- dicate that the baffling as arranged secures the benefit of the counter- current principle within the _ boiler. The casing as it is constructed is insuf- 5—SECTION SHOWING THE MARINE REVIEW HEADER CONSTRUCTION ficiently insulated for high rates of combustion. This can, however, be FIG. 6—PORTION OF BACK FLITCH OR HEADER easily remedied by providing addi- tional insulation, and, if brickwork FIG. August, 1916 is provided with ‘anchor bolts, injury due to panting will be avoided. No distortion of any of the lower tubes was observed, and it is ap- parent that there is no difficulty in giving the lower tubes an ample sup- ply of water. Comments on Design The design gives a very compact straight-tube boiler with good cir- culation. The baffling as arranged gives. a counter-flow action between water and gases through the boiler, which apparently secures very high efficiency. The manner of staying the water chambers is considered efficient, and no trouble should be expected from the, design of the water cham- bers. There is ample space in the header beneath the edges of the lower tubes to allow for the collection of sediment, should this be contained in the feed water. Lloyd’s Register of American Yachts, 1916 edition, 496 9 x 7-inch pages; blue cloth, gilt edges; published by Lloyd's Register of Shipping, and furnished by The Marine Review for $7.50 net. The Register of American Yachts for the current year is of unusual in- terest due to the disappearance of old yachts and the addition of new ones which is indicative of a radical change in the American pleasure fleet. The war is somewhat responsible for the changes among the largest of the steam yachts. Several of the most famous of American pleasure yachts have been placed in commercial ser- vice within the last year or two. A study of the section of the book devoted to diesel engines shows a tendency toward larger vessels with. increased power and speed. One of the most prominent features of the year’s building is the predominance of the naval type. The 1916 register contains the names of 3,589 yachts with the names and addresses of their owners, details in regard to yacht clubs in United States and Canada and the private signals of over 1,800 yachtsmen. 7—STEAM DRUM