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288 facilities, depend upon tug-boats fur these maneuvers. Ferry-boats which are constantly coming in or going out of their slips are provided especially with direction tell-tales which assure the pilot that the engines are rotating in such manner that the boat will ad- vance when he has signalled for ahead motion. Avoidance of serious mishap is thus accomplished. River excursion steamers, whose superstructures are built entirely of wood, thereby requir- ing great vigilance for the detection of misanthropic fires, are supplied with Fic. 3--Eneine Revo.ttion TRANSMIT- TER. Execrric Lamp Type witH DiaL REMOVED, a complete fire-alarm equipment, this system being so designéd that hardly a square yard of the vessel is not guarded by such an appliance. For the assurance of the traveling public it may be well to note here that many of these vessels also carry a sprinkler system such as is now required in many of our land factories. Dredges which hold their working position by means of wooden poles (called spuds), THe Marine Review Fic. 4.--E.Lectric Hetm Inpicator AND TRANSMITTER. which must be manipulated as_ their work progresses, require spud ele- graphs which convey signals from the working platform to the men employed to raise or lower the sptids. So could be multiplied instances of differences in communication equipment for differ- ences in service. Tempting as this sub- ject is, the duty lies before us to de- scribe the. means oF "this Communi: cation and not its varying application. Electricity holds an important place in the transmission of ships' signals, but this place is secondary as regards the movements of the vessels. Those signals which are necessary to navi- gation and maneuvering of the vessel are performed mechanically. The con- trol of the main propelling engines from the bridge or pilot-house is ac- complished by mechanical transmitters connected by bronze wire to receivers in the engine room. Wheels are en- Au gust, 1909 Lamp Type. cased in each instrument traversed by brass chains. To the ends of. these chains the bronze wire is attached. Where corners are encountered triple linked brass chains are led over brass pulleys. In all cases reply~ signals. are transmitted in order that..no con- EG: 5.--ENGINE SHAFT SPEED INDICATOR,