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'TAE. Marine REvIEw . Messrs. Forrestt's special principle, to fold down in a fore and-aft direction. The whole of the deck ironwork, derrick smithwork, etc. is galvanized. The boilers and propelling machinery, illustrated on Figs. 5 to 9, were constructed and fitted by Messrs. Plenty & Son, Ltd., of Newbury Berks. There are two boilers, of the Yarrow patent water tube type (Figs. 8 and 9), having the shells, side wings, and tubes all of mild steel, and constructed for a working pressure of 130 lb. Each boiler is amply suffi- cient to supply steam to the main engines at full power, or to the Clayton apparatus and fire-pump, so that the second boiler serves for emergencies. The propelling ma- chinery consists of two sets of compound surface-condensing engines (Figs. 5 to 7), having cylinders 5 in. and Io in. in diameter, with a 6-in. stroke, feed and bilge pumps being arranged to work from each of the main engines. There iS a separate condenser, of circular form, constructed of galvanized steel plate and fitted with S. D. brass tubes. The combined air and circulating pump is separately driven, and a donkey-pump is fitted for feeding the boilers. The bilge duty is performed by the circulating pump on the Clayton apparatus. One of Messrs. Clayton's "B" type disinfecting and' fire- ~ extinguishing machines is fitted on deck amidships, sup- ported by two 'built-in steel girders fitted under' the deck. ' Machines on this system, as illustrated above (Figs. 10 to 12), have been very largely introduced for fire-extinguishing and disinfecting purposes on board ship and -in docks and harbors. .The method of operation is as follows: The gas generator is always kept charged with ordinary roll sulphur. As soon as gas is required, the engine, which is coupled direct to a blower, is started, a pint or so of methylated spirit is thrown on the sulphur and ignited, and' the charging door of."the generator is closed. The blower immediately com- mences to draw air into the generator through a pipe con- necting the return valve (which is operated by. the - handle FH) with. the upper part of the hold to be treated, from which the air is thus extracted and brought to the generator "(except in the case of cargoes capable of giving off explosive gases, when the air is taken to the generator frorn the: outside atmosphere by a valve operated by the handle K), when the oxygen in the air combines with the burning sulphur, and forms a fire-extinguishing and disinfecting pas... [his gas then passes out through a valve, operated by the handle A along the pipe E, entering the cooler just beneath the engine; it passes through this cooler, in which the temperature is brought down to a normal point, to the blower, and 'is: dis- charged under pressure through a pipe leading to the hold being treated. The air in the hold is by this means deprived of its oxygen, which is replaced by sulphur dioxide gas. The use of Clayton gas is preferred by many to water or steam for fire-extinguishing on board ship, as it must in- evitably reach the seat of the fire, adds nothing to -the weight of the vessel, and has no effect on cargoes of food- stuffs or other perishable materials. For purely disinfecting purposes the Clayton gas machines are largely used in ports all over the world. Vermin can be quickly exterminated, and vessels fitted with Clayton apparatus coming from plague-infected ports are granted free pratique, Clayton gas now being recognized as a sure prophylactic measure against the introduction of plague, cholera, etc. For dealing with open-air fires a fire-pump by Messrs. Merryweather & Sons, Ltd. is fitted forward of the Clayton machine, having a capacity of 4,000 liters per minute, and capable of throwing three powerful jets of water to a dis- tance of. 200 ft. On the trials of the vessel it was proved that she behaved excellently in a seaway. The tests of the Clayton apparatus and fire-pump were satisfactorily carried-out-and afterwards 39 the vessel was dismantled and shipped to Delagoa bay on board a steamer. The Mozambique government promptly accepted the vessel. - THE ECONOMY AND EFFICIENCY OF THE STEAM TURBINE. The London Times is publishing a series of articles on steam turbines, which contains some very interesting data concerning the showing made by machines of the Parsons horizontal, multiple-expansion, parallel, full annular flow type, that are built in England by C. A. Parsons & Co., Willans & Robinson, and. Richardson, Westgarth & Co., in Switzer- land by. Brown, Boveri & Co., and in the United States. by Allis-Chalmers Co., of Milwaukee, Wis. Turbines of this form of construction, with an aggregate capacity of over 1,000,000 H. P., are now operated in various cities in Europe and the United States for the generation of electric power. Several of the turbines in operation at the plant of the Newcastle Electric Supply Co. are each capable of developing 6,000 H. P. at 1,200 revolutions, under normal conditions, and over 10,000 H. P. on overload. Tur- bines of similar size and design, put in operation in Switzer- land by Messrs. Brown, Boveri & Co., are each designed for a normal output of 12,000 H. P., while similar progress is being made by French'and Austrian engineers, The success of marine turbines for torpedo boat destroyers and high speed passenger vessels has been so widely dis- cussed, both in the technical and popular press, that very little remains to be said at the present time; but the Times makes some very. significant comparisons showing the results at- tained with vessels of identical construction except for the type of engines used. The Amethyst and the Topaz, con- structed after the same pattern, were selected by the British Admiralty for the purpose of making a series of exhaustive - tests. the former being equipped with turbines and the latter with reciprocating engines. The contract speed of the vessels was 2134 knots and the tests showed that at all speeds above 14% knots the turbine equipped Amethyst was more 'economi- cal, namely: 15 per cent at 18 knots, 31 per cent at 20% knots "and 30 per cent at 21 I-10 knots. At full power in each' véssel the Amethyst showed 42 per cent more than required by contract on. the coal allowed. The Amethyst also reached a speed of 23.5 knots during these tests and the Topaz only 22.1 knots. AS "More noteworthy results on a larger scale have recently been afforded by the trials of two Cunard liners, the Car- mania and the Caronia, each of 30,000 tons displacement and 23,000 I. H. P., the former being fitted out with turbines and the latter with quadruple expansion engines of the latest design. Essential facts concerning the trials of these vessels have been widely published and generally read; but that statement that the Carmania beat the Caronia by about one knot does not give an adequate idea of the relative efficiency and economy of the turbines. It must be remembered that one knot in speed means about 16 per cent more horsepower and that, therefore, the Carmania would appear to be about 16 per cent more economical than her sister vessel driven by the most highly developed type of reciprocating engines; further, that the test of the Carmania' was the first trial of turbines on so large a scale, and it may reasonably be ex- pected that improvements in detail will improve upon the noteworthy results obtained. Members of the engineering profession will await with great interest the trials of the two gigantic Cunard 'turbine vessels of 25-knot speed and 60,000 to 70,000 H. P. now building on the Clyde and the Tyne. The Nantasket Steamship Co. will issue $100,000 worth of new stock to partly cover the cost of the new steamer building for the company at the yard of the: Fore River Ship Building Co., Quincy, Mass.