The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

14 | MARINE Modern Search Lights. The use of electric search lights on board vessels, not only of the navy, but also those of the merchant marine, as well as on yachts, has, within recent years, been steadily growing, as impovements in the mir- rors and the operating and contolling mechanism have given to vessel owners and the government reliable projectors. The search light is now a necessary part of the equipment of naval vessels, and all passenger ships or steam yachts of any pretentions have pilot house projectors. In. the manufacture of a perfect search light there are two main SEARCH LIGHT 'TESTING TOWER, SCHENECTADY WORKS OF THE GENERAL ELECTRIC CO. parts, the lamp and the reflecting surface, each of which must of itself be perfect. Unless the greatest of care is given to the design and workmanship of the lamp and the grinding and polishing of the mir- ror, the result must. be failure or only semi-success. Up to quite re- cently, the mirrors for search-lights manufactured in this country were imported. from Germany and France, but when the General Electric Co. decided upon the manufacture of projectors on an extensive scale, it cast about for a manufacturing optician who could be trusted to es velop mirrors of as high a grade as those of European make. At the works of the General company in Schenectady, N. Y., one entire de-. partment is now occupied in the manufacture of projectors. On one of the large number of buildings a.square tower has been erected carry- ing a railed platform, and it is from this tower that tests are made of the power and range of the search light beams, which sweep over the wide expanse of the valley of the Mohawk.. A system of distance and intensity has been calculated, by which the carrying power of the beam is guaged and the capacity of the projector tested. SEARCH LIGHT REFLECTORS, The light reflecting surface is a silvered glass concave lens, so ground that when the are of the lamp is in its focus the reflector Pea which proceed from the mirror are parallel. Two types are used, the Mangin and the parabolic, the former having two spherical surfaces of different radii, the reflection and refraction causing the rays to be pro- jected in.stvaight lines, and the latter having true parabolic surfaces. Still a third type, the hyperbolic, is used:where the illumination of a _izontal type has been found the most suitable. REVIEW. large area at short range is desired, but in this case the mirrors are of metal silvered. Lamps are of two types, inclined and horizontal, ac- cording to the position occupied by the carbons. Both lampsare auto- matic and focus in feeding. The first type is used in the 12-inch pro- jector, with either type in the 18-inch, while for larger sizes. the hor- All the lamps are de- signed to operate on direct current incandescent circuits, a regulating rheostat being connected in series with the lamp to pane the Voltage to that point at which the best results can be obtained, which is from, 40 to 60 volts according to the current taken. In order that the person controlling the direction of the beam may most satisfactorily direct it, three systems of control have been devised --pilot house, rope and Becca depending upon the location of the projector. Electrical control can be applied to any size, but is best suited to the 24-inch and larger sizes. ment of the drum containing both lamp and mirrors is given by two small motors, which are concealed in the pedestal at the base, and controlled by asingle lever set on asmall pedestal containing the resis- tance and switches. almest any distance from it. necessarily a limited. When the projector is set on the pilot house of a steamer, pilot.house conrol is ususally employed, the actuating rod passing down through the roof of the pilot house, and. terminat-. ing in a lever movement, which givesthe necessary horizontal and, vertical deflection to the beam. The standard sizes of these search lights are based on diameters of the reflecting lenses--12, 18, 24, 30, 36 and 60 inches. search light in the world, that exhibited by the General company at the Chicago exposition, was of the 60-inch type. This light is now on - the top of Mount Lowe in California, from which point its beams Are, visible many miles over the waters of the Pacific. = Roberts Water tube boilers seem to be in special favor on steam vessels in use by various departments of the government. Among ves: sels of this kind to which Roberts boilers have been furnished are the. following: . Snag boat Mandan.on upper Missouri river; dredges, Ohio commandant's barge Minnie, Brooklyn navy yard; torpedo planter Dyne, Whitestone station; revenue cutter Penrose, Pensacola station; revenue cutter Tybee, Savannah station;. reyenue cutters Scout and Guard, Puget sound station; revenue cut- : ter Johnson, Detroit station; war department steamer Reid Whitford, Georgetown station; war ereennent steamer Angler, Savannah, sta- and Oswego on Ohio river; tion; war dgnoamaan steamer Gen. Geo. Thom, Newbern station; United States harbor supervisor's steamer Alert, New York station; United States harbor supervisor's steamer Active, New York station; United States harbor supervisor's steamer Argus, New York station. Roberts boilers are also used in the New York city police boat In- spector, the New York city dumping boat Cinder-Ella, and the quar- antine commissioner's steamer State of New York. It is quite probable vhat the big Northern line passenger steamers North West and North Land will next season make a better showing on time schedules than they have made at any time since they were built. Engiyes and boilers have been undergoing a general overhauling all winter and it is announced now that the chief engineers will be two men who have had considerable experience with Belleville boilers on ocean- going ships, and who will give attention mainly to the boilers, as they will have other first-class engineers to look after the engines. Solid through sleeping car trains with dining cars attached are operated by the Nickel Plate road between Chicago, Cleveland, Buffalo. and New York City. Through sleeping-car to Boston. - 8 Mar 81 .S. ENGINEER OFFICE, 1101 D. S. Morgan Building, Buffalo, INig oN February 15,1897. Sealed proposals for harbor excavation "and construction. of timber and concrete breakwater at Dunkirk Harbor, N.Y., under continu us contract, will be received hare until 11 o'clock A. M:, Monday, March : , 1897, and then opened. Information fur- nished on application. T. W. SYMONS, Major, Eng : j Mar. 11. Horizontal and vertical move-. By throwing certain disengaging clutches the electrical control may be cut off and the projector controlled by hand. Electrical control allows the projector to be operated from a point The same result may also be attained at less cost by means of the rope control, horizontal and vertical movement also being attained by the movement of a single lever, In this ease, however, the distance between operator and lamp must The greatest gee ; at : 3