I50 THE GYROSCOPE FOR MARINE PURPOSES. 



devices, which are shown in Plate 52, involved changing the center of gravity 

 of the vessel and thus introduced an additional disturbing and unstabling 

 element which required additional treatment; his device involved a great 

 moving weight running as high as 5 per cent, of the total displacement of 

 the boat and a very large amount of hydraulic machinery for handling 

 these weights and a considerable amount of motive power for operating 

 them. But with the active type of gyroscope, we find that a small part of 

 I per cent, of the displacement of the ship will perform a very substantial 

 service, down to the point of practically fully extinguishing the rolling. 

 By the use of this device there is entire absence of any shift of the center 

 of gravity of the vessel, and its stability remains unchanged. The sizes, 

 weights, speeds and location of a gyroscope for this purpose are among the 

 points which have been canvassed in tests carried on at the Washington 

 Navy Yard during the present year. 



Plates 55 and 56 show front and rear views, respectively, of a working 

 model of a 26,000-ton battleship of the super-dreadnought class, with five 

 feet metacentric height and eighteen seconds period of roll, capable of 

 rolling through a total arc of 60 degrees; means are provided for autograph- 

 ically recording all motions, both of the ship's model and the gyroscope, 

 upon same. The gyroscope was operated both passively and actively; 

 means were also provided for emplacing the discharge of the active gyro- 

 scope variously with regard to the ship's oscillation so that the effect of 

 different combinations might be studied. Many other auxiliaries were 

 provided, one of which permitted the actual velocities of the gyro wheel 

 to be counted while in operation. This was accomplished by the strob- 

 oscopic apparatus of Capt. D. W. Taylor, similar to that used by him in 

 his investigations of propellers under service conditions; in fact, both 

 the ingenuity and reliability of performance of the model ship and the 

 auxiliaries are directly due to Captain Taylor and his assistants at the 

 Washington Navy Yard. By means of this very complete equipment 

 studies and records have been made and charts of performance prepared 

 and other valuable data accumulated, much of which is new, as many of 

 the observations, we believe, were never before undertaken. The investi- 

 gations with the active type of gyroscope are in a new line of research ; the 

 results obtained are important in point of much more perfect control of 

 the ship's roll than heretofore possible. 



Captain Taylor has prepared a very full report upon this work forming 

 a part of which is a forty-page appendix in which he treats the question 

 in a most masterly manner under some sixteen heads. In this most unique 

 and valuable work. Captain Taylor has given an original mathematical 



