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a , TAe MARINE REVIEW are stationary or guide blades, whilst the blades fitted on the drum are moving blades. The diameter of the drum is less than the cylindrical case, and 'thus an annulus is left between the two, which is 'occupied by the blades referred to. Steam issuing from the boilers flows through the first row of fixed or guide 'blades on the cylinder; it then, in jets of moderate velo- city, impinges on the moving blades, and imparts to them a rotary motion, this process being repeated on each suc- cessive ring of fixed and moving blades throughout the turbine. The areas of the steam passages through the blades gradually increase from one end of the turbine to the other, to correspond with the expansion in volume of the steam for the range of pressures from beginning to the end of the turbine. In the exhaust casing . of each of the low-pressure turbines a reversing turbine is fitted. By means of suitable valves, when manetuver- ing, the low pressure and astern on each side of the vessel are capable of being worked ahead or astern, as required, independently of the high-pressure turbine (the high-pres- sure turbine under such conditions running idly in a vacuum.) By this arrangement the vessel has all the maneuvering qualities of a twin-screw vessel. In torpedo boats a similar arrangement is adopted as in the Turbina, viz., three in series, with one astern on the center shaft only. This arrangement permits of a reduced weight be- 'ing obtained, as compared with the high-pressure and two low pressure in parallel for equal efficiency. In very large 'powers it is desirable to divide the power over four shafts, thereby increasing the revolutions and reducing the size of the units. The four-shaft arrangement lends itself well to large war vessels, as two complete sets of engines are 'obtained, viz., one high-pressure and one low-pressure, _-with condensing plant in each engine room. A two-shaft arrangement of machinery was adopted in the yacht Nar- -cissus, which, as previously described, gave very good results; but for powers over about 2,500 to 3,000 a two- shaft arrangement entails additional weight. On account of the greater range of expansion dealt with in the tur- 'bine, as compared with the reciprocating engines, a good vacuum is much more essential in the former than in the latter, and because of the importance of a high vacuum with the steam turbine careful consideration requires to be given to the condensing plant. se NEW VACUUM AUGMENTOR. With a view of maintaining a high vacuum Mr. Parsons has designed a new apparatus, to assist the ordinary air pump and condenser, termed "vacuum augmentor." The augmentor consists of a small steam jet placed in the con- tracted portion of a pipe, led from the bottom of. the condenser. The jet draws air from the condenser, and delivers it to the air pump through a small auxiliary cooler. By this means the air is reduced to a negligible - quantity, and the vacuum in condensers can be higher 'than in the air pump, thus increasing the efficiency of the 'machinery. The vacuum augmentor has now been fitted in several vessels, with very good results. In the Vir- ginian and Manxman the rise in vacuum due to the aug- mentor was 1% to 1%4 inches, representing an additional - economy of about 7 per cent to 8 per cent. The steam used by the jet is about 1%4 per cent, leaving a net gain of about 6 per cent. The effect of an increase in vacuum of one inch at. 26 inches has been found to de- 'crease the consumption by about 4 per cent and for one inch at 28 inches about 6 per cent. By later refinements 'the steam used by the jet is under one per cent. Another point which has been greatly discussed in con- nection with turbine machinery is the question of boiler 'pressure. The effect of difference of boiler pressure be- tween 150 pounds to 200 pounds is relatively smaller with turbines than with reciprocating engines, and it is very questionable, in the majority of cases, whether the saving in coal by the adoption of high boiler pressure would justify the increase. More especially is this 'the case in moderate speed vessels, where the turbines are some- what larger for the 'power as compared with higher speed vessels. In such cases the turbines could be designed to have their full measure of economy with boiler pressure not exceeding 150 pounds. The question of astern power was very freely criticized in the earlier vessels fitted with turbine machinery, due perhaps to the fact that the pro- portion of power provided for astern was somewhat on the small side. In more recent vessels a larger proportion of power has been provided, as circumstance demanded, and very good maneuvering qualities have thereby been obtained. : Other advantages incidental to the turbine might be cited, such as reduced weight of machinery, steadiness and smoothness of running, reduction in oil and stores, and absence of racing in a seaway, and other advantages which have brought the turbine to a commercial success. So rapid has been the development of the marine turbine that the Turbina Company have found it necessary to make arrangements with other builders to manufacture turbines. There are, at the present time, about 25 of the leading ship building and engineering firms in this country, in addition to foreign licensees, who have acquired the license to build Parsons' turbine engines. The 'Parsons turbines have also been built in Germany and fitted to.a torpedo-boat destroyer and cruiser for the German gov- ernment, which vessels have given very satisfactory re- sults, and other orders have since been booked. The United States government have placed an order with the Bath Iron Works, Bath, Maine, for a scout cruiser of 24 knots speed to be fitted with the Parsons turbines, and orders for four passenger vessels have been placed with the Parsons Co.'s licensees in the States. A detailed list of turbine vessels which have been built in this country up to date shows. a total horsepower actually completed of about 250,000 I. H. P. In conclusion, it may be men- tioned that the total horsepower of turbine engines com- pleted and on order with the Parsons Company and their licensees is over 800,000 IJ. H. P. : PERSONAL. Charles P.-Wetherbee has been elected a director of the Bath Iron Works. Mr. Alexander Hynd, Western Reserve Building, Cleve- land, will represent the National Metallic Packing Co., of ' Oberlin, in the marine trade at Cleveland. Mr. Arthur Giesler has opened an office at No. 170 Broadway as a consulting engineer and will devote him- self to hydro-turbine power plants and hydro-turbine pumping stations. Wm. P. 'Kirk of Toms River has commenced to plank the 65-ft. houseboat he is building from designs by Cox & Stevens and will make delivery by the middle of April. The motor power will be a 25 H. P. Standard engine. This boat will only draw 24 in. and can go in any harbor or river along the coast. The steam schooner Tamalphais was launched at the Mathews, McWhinney & Starritt ship yard at Hoquiam, Wash., recently. She was built for the E. K. Wood Lum- ber Co., Hoquiam, and can carry 550,000 ft. of lumber. She will also have accommodations for a few passengers.