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TAE Marine REVIEW STROCCO CASED FAN FOR STEAMSHIP PHILADELPHIA. type the blades or vanes are usually of greater length radially than their face measurement parallel with the fan shaft, while the number of blades is generally trom six to 12° In the "'Si- rocco":fan, however, the radial meas- urement of the blades is much less than their face measurement parallel with the shaft, and 64 blades are or- dinarily employed, the tips being curved forward in the direction of ro- tation. This construction, as a whole, was at the outset considered by scien- tists as incapable of setting up true centrifugal action, and the fan was de- scribed as a squirrel cage of lathes which merely impelled the air by im- pact; further, it was stated that while this arrangement might: do for low 'pressures, or free discharge, it would be useless against high water gages or inelastic "fttids. such as «water: AH these ideas have, however, been con: tradicted, by: facts)as it = has cbéen proved that the fan acts as efficiently up to 30 in. water pressure as at 1 in, and, further, it has-equal ability with a centrifugal pump for water with high or low lifts apart from its efficiency in the propulsion of air. The blades are curved forward in the direction of rotation, with the re- sult that not only are noise-producing and power-absorbing eddies eliminated, but the velocity of air discharged is so greatly accelerated, that it exceeds the peripheral speed of the blades by more than 70 per cent. In a number of tests the speed of discharge has ex- ceeded the rate of rotation of the tips of the blades by from 70 to 80 per. cent. "This -is an important factor 1m determining mechanical efficiency. For example, ina 25-in. "Sirocco" fan in 31 3,532 lin, ft. per minute, shows a very high degree of efficiency per unit of power. These advantages, combined with the fact, already noted, that the tur- bine type centrifugal fan occupies about only half the space required for paddle wheel blowers, is sufficient ex- planation of the steadily increasing number of "Sirocco" -- imstallations found aboard ship. Until this year "Sirocco" fans were built only at Bel- fast, Ireland, 'by Davidson & Co., who have the largest plant in the world de- voted exclusively to fan making. The American demand is now supplied by the Sirocco Engineering Co., 138 Cedar street, New York, whose lately com- pleted manufacturing plant is located at Troy, N, Y. Improvement of the Chicago river would make the city the greatest ma- rine ship building, manufacturing and 714-IN. SIROCCO BLOWER DIRECT-CONNECTED TO ELECTRIC MOTOR. actual use at 300 R. P. M., the tips of the blades have a speed of 1,962 it. per minute. The actual velocity of the air is 1,962 plus 80 per cent, or 3,552 ft. The volume of discharge, 8,000 cu. ft. per minute, figured at a velocity of, FOUR OF TWENTY SIROCCO FANS FOR VENTILATING STEAMSHIP MAURETANIA, commercial center in the world. That was the prediction of Albert H. Scherzer, made before the city harbor commission yesterday. Mr. Scherzer said that he could see no necessity now or in the future for a harbor on the lake front. He suggested that the lake front be reclaimed for a distance of three miles out and developed into sites for parks, public buildings and works of art. Lieut, Col. Townsend, government en- gineer, with headquarters at Detroit, is at present making a tour of the various harbors under his jurisdiction upon the government steamer Hancock.