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May, 1914 fire. The only feasible way of re- stricting fire in a ship is by vertical fireproof bulkheading. The means adopted for this purpose are shown on the annexed sections. The problem of economical propul- sion is one that is not solely confined to the matter of obtaining an eco- nomical prime mover. Often fuel econ- omy means a _ larger engine, and hence a reduction of cargo capacity. It has been found that unless the dis- tance between coaling ports exceeds 2,000 miles there is no advantage in fitting quadruple instead of triple- expansion engines. The author is not convinced as to the economy of the combustion system of machinery. The question of stability is one of great importance. It is highly de- sirable in passenger ships that they should be comfortable, and comfort is largely measured by the metacen- tric height. This has been growing in recent years, although from the point of view of easy motion in a seaway it is desirable to keep the metacentric height in the loaded condition as small as may be compatible with safety. The relation between metacentric height and rolling period is now re- ceiving more general consideration and is actually taken into primary consideration in the design of anti- rolling tanks. The Cunard Co. have experimented with the Frahm _ tank on the Laconia, and the results of this experience is the fitting of them into the Aquitania, in which case bilge keels are being dispensed with. This paper is a very valuable con- tribution to the subject of design of ships, and shows how very much alive the naval architect of today has to be in order to keep up to date. Direction of Sound David Wright Smith, 212 St. Vincent street, Glasgow, is marketing a device intended to locate sound in fog. It is supplementary to the ordinary whistle and is intended to be sounded imme- diately after it on the approach of another vessel. The direction of another vessel sounding this signal in fog can be at Once located to a single degree. At the second or third blast the course of the other vessel can be deduced from the difference, if any, in the bearing, and the presence or absence of a dan- gerous position will thus be early de- termined. The signal consists of a loud hissing sound, and the sound producer is shown at Fig. 1 overleaf. It is ac- tuated by an ordinary stop-valve and lever and is fitted to a branch from the steam pipe supplying the whistle. THE MARINE REVIEW One striking advantage which this signal possesses is, that it will be hardly, if at all, returnable by an aerial echo; so that, if heard, it may FIG, 1--SOUND PRODUCER, FITTED ON BRANCH FROM STEAM PIPE SUPPLYING THE ORDIN- ARY WHISTLE be taken to be proceeding direct from the source. Two forms of receiver are shown. Fig. 2 is suitable for a bridge where the rail is covered with a wind screen. Fig. 3 is adapted for the top of a deck house. The concave reflector shown can be readily unshipped and stowed away when not in use, the pedestal with the indicating plate being a per- menent deck fitting. On a whistle being heard, the direc- tion of which is required, the. officer, having the ear pieces in his ears, grasps the handle, releasing the spring clip from the grooves on the under side of the brass indicating plate, and | erase errr FIG. 2---SOUND RECEIVER FOR USE ON BRIDGE 199 Swings the reflector rapidly through a few points of the compass, covering the direction from which the whistle is supposed to proceed. If the other vessel sounds the supplementary sig- nal, the hissing sound will be heard through a small arc, and the clip will be released at the position of maxi- mum intensity. As the ear pieces block out the sound of the signal, except what comes through the ear tubes, the signal is not heard at all, unless the apparatus is pointing approximately in the direc- Ja 3 | Lo 3 -- SOUND RECEIVER FOR USE ON. TOP OF DECK HOUSE EEG. tion of the sound source, and this fact makes a mistake as to direction im- possible. The Great Lakes Protective Asso- ciation, which carries 25 per cent of the insurance upon vessels enrolled in the association, has fixed the rate at 314 per cent for the year, which is a reduction of % per cent from the rate obtaining last year. It is also % per cent lower than the rate established by the underwriters for the coming season of navigation. The associa- tion, however, hereafter, will not take a partial form of insurance, that is, insurance will not be written for total losses only or collision damage done or sustained. The valuation of the five wooden vessels enrolled in the association was reduced from $25,000 to $20,000 in each case, and the asso- ciation will accept the rate fixed by the underwriters for this class of ton- nage. The Hartmann-Greiling Co., Green Bay, Wis., has been awarded a number of large boat rebuilding contracts,' among them the construction of a new steel hull for the tug Bob Teed, owned by the Greiling Bros. Co.; new boilers-and other improvements to the steamer Albert Soper, and general re- pairs to the steamer Frances Robbins, owned by the Becker Steamship Co., Cleveland.