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May, 1919 the bottom of the resultant grooves causes intensified corrosion. Initial compression stresses do not seem to favor corrosion, Annealing after the first drawing, at a temperature of 400 degrees Cent. or thereabout removes internal strain and produces a finely grained micro- structure, with none of the coarse struc- ture which results from annealing at temperatures within or above the crit- ical range. Fair success has been ob- tained by springing brass rod so as to obtain compression stresses in the sur- face; possibly similar results may be achieved in the case of tubes. Careful specification of condenser tubes is important in reducing mainte- nance costs and in reducing contamina- tion of hot well water. Electric Propulsion of Vessels A general description of some of the results recently: obtained in the propulsion of vessels by electricity, not confined to one country but giv- ing a general idea of world-progress, was described in a recent isstie of the Journal of the Engineers' Club of Philadelphia. After pointing out that for land work the steam turbine is rapidly supplanting reciprocating engines where large units of power are required, and noting that such 'progress has been slower in shipping, the author proceeds. to describe some actual installations. The motors and speed-reduction gears of the steamship Wuotsty CASTLE are described. Each of the packet boats Hetropotis and Cairo had three pro--- : pellers, running at 350 revolutions per minute. The France had four pro- pellers running at 250 revolutions per minute and the Lusiranra four, run- ning at 190. Other vessels are de- scribed in which reciprocating engines and turbines are both employed. The hydraulic reduction gear of Fottinger was used in a tug of 500-horsepower in the port of Hamburg, also in a large 'mail boat, the KoninceN-LuIsE, sunk by the allies early in the war. The Cunard Co.'s vessel TRANSYLVANIA has reduction gearing and two propellers running at 128 revolutions per minute. The electric transmission of power, however, obviates many of the diffi- culties encountered with mechanical - gearing, and the reversibility is perfect. The arrangement of the plant on the steamship Myotner is described. The electric generator is coupled direct to the steam turbine, being a 3-phase syn- chronous machine which supplies cur- rent to an asynchronous motor. Two such motors each developing 450-horse- power drive the propeller shaft through gearing, the result being that while THE MAKINE. REVIEW the turbine runs at 7200 revolutions per minute the propeller runs only at 90, owing to. the electrical and me- chanical reduction in the ratio of 80 to 1. In actual practice the speed of the propeller can be reduced to 12 revolu- tions per minute by the use of resist- ances in the electrical circuit. Reinforcing Frame for Concrete Ships Builders of concrete vessels are con- fronted with the important problem of efficiency reinforcing a hull built of practically unyielding material so that it will successfully withstand the stresses ROSA (am Ea oo i oil i N gd ere eae We ts if 4 DETAILS OF FRAME CONSTRUCTION FOR : . CONCRETE VESSELS ~ and strains. brought to bear upcn_ it while laboring in a heavy seaway. To provide 'means of reinforcing a concrete vessel, both longitudinally and transversely, Cotter T. Bride, Washing- ton, recently obtained a patent on a re- inforced ship. The invention provides for a double reinforcing frame with means for tying the outer and inner frames together. This construction is shown in the ac- companying illustration, in which A are the reinforcing bars which run from the keel to the deck, while the bars B are laid longitudinally. The tie pieces C are arranged at convenient intervals and fasten the two frames together. _ The upper illustration is a midship section of a vessel reinforced in the manner described. This is a double- decked vessel and, as indicated, the same arrangement as shown in the lower view is used to reinforce the decks. It is pointed out that the frames are so con- structed that they can be assembled by comparatively inexperienced labor. The _welding, etc. 234 bars C are made in two designs, one. to run crosswise and the other. diagonally. These .are readily formed: by cutting off from bar stock and punching the holes to accommodate the reinforcing bars. Thus, once the design is decided upon it is a comparatively simple matter to fabricate as many thousand of these pieces as are necessary. It is said that the reinforcing frame is adapted for vessels that are poured in molds or for those wherein the plastic material is spread on with trowels or other similar tools, according to the Italian practice. To Investigate Welding With the object of thoroughly in- vestigating all branches of welding, the American Welding society was recently formed. This society will take up the work begun by the welding committee of the Emergency Fleet corporation dur- ing the war. The object of the society is to bring together persons from all branches of industry where welding processes are used. ,These processes include forge, electric resistance, spot, arc, gas, thermit Six degrees of member- ship are included. These are arranged to accommodate all classes of manufac- turers interested in the subject of weld- ing as well as to provide a class for honorary membership. The. society will carry on exhaustive research work from the simplest to the most complicated characters. Among tentative plans for. this work are the determination of the best current to use ior various kinds of electric welding, proper methods for making up both gas: and electric welds, determination -of proper angles" of bevel for plates to be welded, change in metal character- istics caused by welding, methods of assembling to eliminate stresses, react- ance in long gap spot welders for thick plates, relative value of various forms of joints and methods for inspecting and testing completed work. The subject of standardization will be - given careful consideration and the con- clusions arrived at are to conform to the procedure established by American engineering standards. The society also will take an active part in planning how welders should be trained and how their proficiency is to be determined. Official inquiry into the wreck of the Princess SopHiA, which was wrecked near. Skaguay, Alaska, last October, with a loss of 300 persons, is still under way in British Columbia. The only survivor of this mishap was an Fnglish setter dog which swam ashore and appeared days later in a famished condition at a camp.