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330 transmits the torque, but communicates no longitudinal thrust to the turbine, as the engaging lugs of the coupling do not come into direct contact, but have ball races inserted between them to permit free longitudinal motion. The worm-drive shown beyond this actuates a counter registering the revolutions of the propeller. "Referring back to Fig. 1, a series of pipes are shown leading away from the propeller-shaft sleeve through the casing of the tank. .These. serve. to measure the water pressure on the THE Marine. REVIEW showed that near the tips the discharge from the propeller was as it is ordi- narily assumed to be, but with certain models experimented with, a negative flow was indicated in the neighborhood of the boss. In this region the blades were apparently acting much as if they were portions of the impeller of a centrifugal pump, drawing in water near the axis, and discharging it further out. Again, with a propeller | 12 in. in diameter, having wide-ended blades, the efficiency was diminished by 50 per cent on reducing the diameter ] LD N A G Dy BS AREZZO (a September, 1909 testing of propellers up to 4 ft. or 5 ft. diameter." We hope for the further courtesy of Mr. Westinghouse in the results of tests carried out with this appar- atus. : NEW MISSISSIPPI NAVIGATION Co. It has been announced that the nec- essary preliminaries toward the or- ganization of a $5,000,000 corporation to own and operate a line of flat-bot- tomed steel freight boats on the Mis- Lee © Q PONG Ges S LY Z } ° QO} qe itt} I i: ie WA WT wos EIR '. aX ay Fic. 2--PLAN oF APPARATUS, ARRANGEMENT OF Motor AND THRUST-WEIGHING DEVICE. propeller blade or boss, at any point desired by connecting them up to holes appropriately drilled for the purpose. Some very interesting results have al- ready been obtained, as to the distribu- tion of the water pressure over the blades and boss. Thus it has been found that along the whole of the mid- dle line of the driving face of the propeller blade a negative pressure is indicated. In other experiments an ex- ploring tube, fulfilling the function of a pilot gage, points in the wake of the propel'er, but 'quite close to the latter. was fixed at different This gage to 10 in. thus affording further evi- dence that the inner portion of the propeller was doing little or no useful work. In some other experiments a better efficiency at high speeds was attained with a model of finer pitch with greater area than the standard type generally adopted for turbine vessels. "The tank in which these experi- ments were made was. 24 {t, in di- The speed of the propeller tips reached 12,000 ft. per minute, and ameter. in some of the trials as much as 400 A tank 50 ft. in diameter would suffice for the horsepower were absorbed. sissippi river, are practically complete and it is probable that the project will be launched shortly. W. K. Kavanaugh, president of the Lakes-to-the-Gulf Deep Waterways As- sociation, will probably be the presi- dent of the new corporation, which is to be known as the Mississippi-Pan- ama Navigation Co. Headquarters have been established at St. Louis, Mo. Governor Charles S. Dineen and Sen- ator William Lorimer, of Illinois, will be among the directors. The route of the flat-bottomed steel boats will lie between St. Paul and New Orleans. é 4 ¥ 3