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also the outer covering must be securely bridged across to form the return wire. The single wire system has now almost been abandoned. It has a few advan- tages, but many disadvantages. More- over, it cannot be carried out in its en- tirety, as if the lighting of any panelled cabin is required double wiring must be used, and the return carried to the near- est ironwork. Also in the vicinity of a compass the wires must be doubled. Where it can be carried out it is sim- ple, easily repaired,» and faults can be easily traced, since they can only occur on one wire. The trouble arises from the joints with the hull. Any joint be- tween dissimilar metals, with an electric current passing as well, are soon cor- roded, and a bad connection will result sooner or later. With regard to fittings, these are gen- erally of the stiff, pendant type, or bulk- head fittings, with heavy. glass fronts. For cabin lights, etc., the same type of fittings made in fancy designs is used. These fittings are so arranged that they move solid with the ship, and, therefore, a steady light is maintained whatever the motion. For mast-head and side-lights special appliances can be obtained to prevent the lights going out through failure of lamps. Some are designed to advise those in charge by ringing a bell and indicating on a special instrument that a lamp has gone out. Perhaps the simplest is the double filament lamp, with two separate filaments, both in use. If one goes, there is still a reduced light from the other: Upon, say, a periodical examination, this fault can easily be remedied, and the lamp used in a less important position. GENERAL MAINTENANCE.--With regard to the general maintenance of the instal- lation it will be well to mention a few. important points which are likely to oc- cur. The dynamo should need little look- ing after if ordinary care is used. The commutator will give most trouble, chiefly from sparking. On no account should sparking be allowed to continue. If it cannot be done away with, then it may be from the following causes: (1) Wrong position of brushes, which can be remedied by revolving them round the commutator until the correct position is found. (2) Sparking may occur from a fault on the armature or a disconnection in the coils. .This can only be repaired by removing the armature and repairing the damaged coil. This fault should not occur under all ordinary uses, but it is preferable to carry a spare armature. (3) From flats or unevenness on the sur- face of the commutator. This might be got over by filing and the use of glass cloth if not too bad. If it is badly burned then the only satisfactory rem- edy is turning up in a lathe; or by a tool rest rigged up on-the bedplate. (4) By en "TAE. MARINE. REVIEW insufficient contact between the brushes and commutator. This can usually be adjusted by altering the whole brush holder or by adding pressure to the brush only. Care should be exercised in this matter, and the pressure kept to a mini- mum. Heavy' pressure is unnecessary and means wear of commutator and brushes. It is important that all connections are kept tight, especially in the magnet cir- cuit, as a break in this is a dangerous matter. Attention to the switchboard is a small 35 lamps, etc. Also a diagram of connec- tions for testing either for faults to the ironwork or faults between lead and re- turn. ITEMS OF GENERAL INTEREST. Fire Commissioner Francis J. Lan- try, of New York city, has awarded contract to Alex. Miller & Bro. for the construction of a fire boat to be 102 ft. in length. Two other fire boats are also being built for the city by the same firm. Construction at Bath, Me., includes two vessels; the G. G. Deering Co. is oR, EXTENSION -Box- 1 beware matter. Probably the switches will be suet : | SWITCHES NEGATIVE i roses?) fc 1 eA INCOR NSD ee NS ele MAIN H { SWITCHES |, | ' - AND- f] ; FUSES - cel oe '9 SHUNT MAGNET O1LS- \ .@ of O © SERIES MAGNET Cos: 0 To FAULTY Circuir . CONNECTIONS Fen TESTING EARTHS "SHORT cl1recviTs- HE be 1RON WORK o a ° TO POSITIVE TO NEGATIVE LEAD ~ LEAD DIAGRAM OF SWiTCHBOARD AND CONNECTIONS. rarely used under current, and if any burning does take place it is easily taken off with a file and glass cloth. The principal maintenance on the cir- cuits will be the renewal of the lamps and occasionally a fuse, if faults should occur. The tracing of a fault is an easy matter in circuits where disconnection of any part is so easy. Assuming that a fault has occurred, the circuit upon which it is can be traced from the switch- board. The next step would be to draw all the fuses in the distributing box on the circuit and again test. This would show whether the mains were right. Next each branch could be tried from the box and the faulty branch further disconnected at the extension box, and so on until the fault is found. System must be employed in looking for a fault, and by starting at the beginning of the circuit and working to the last branches any fault either to the earth or iron- "work, or between lead and return, can soon be found. A few cells and a gal- vanometer or detector are all that is necessary and can easily be handled. Tests should be made each morning when shut down. The attached diagram shows a switch- board and one circuit complete with constructing a 1,400-ton four-masted wooden schooner, and the Kelley- Spear Co. will soon launch the dredge - which it is building for C. M. Cole, of. Fall River, Mass. The. Cunard Steamship Co. has de- clared a dividend of five per cent and after writing off for depreciation the usual amount, has carried $600,000 to the insurance fund and $250,000 to the reserve fund, leaving a balance of $270,000 credited to profit and loss ac- count. . A successful trial trip of the new wrecking steamer Helen M. Field took place recently. The vessel is 160 ft. | in length, 28 ft. wide and 12 ft. 6 in. deep. She has double fore and aft compound engines of 700 H. P., built by James Reedy & Son, Baltimore, and there. are two 10 x i2 Scoteh boilers. A bill was recently introduced at Al- bany to authorize the construction of | a water gate and monument to Robert Fulton, inventor of the steamboat. It provides for the extension of River- side park in the city of New York, by the filling in of lands now under water, and the erection of the monument on the land so made. © : '