December 21, 1893] 



NA TURE 



177 



It was somewhat remarkable that in this same year in 

 the Navy, just, it might be said, when the means of fully 

 applying the experimental method to fleet manoeuvring 

 became available, the tide set strongly against experi- 

 ment. The recommendations for experiment were cur- 

 tailed, and special promptings and means for carrying out 

 experiments, which had been usefully employed for four 

 years, were withdrawn. The feeling grew that what had 

 been done in 1865 was sufficient for all time ; and those 

 who were responsible for errors and shortcomings in 

 1865, because of the defective means for experiment, found 

 themselves met by the stubborn character of their own 

 mistakes when they desired to amend them. The Navy 

 became too satisfied with the work of 1865, and felt in 



powers has shown less apparent variation in the move- 

 ment of ships under given conditions ; and when, with 

 any given method, the observers grow skilled, the ap- 

 parent variations of movement become less. The accuracy 

 of movement of all ships at speed when turning is re- 

 markable. The curve traced in Fig. 8 is the mean of 

 three turns of 180'' to the right, made by the Edinburgh, 

 at an original speed of twelve knots, and with a helm- 

 angle of 34°, reached, by means of steam steering gear, in 

 II seconds. The small circles represent the successive 

 positions fixed by observation when the turn had reached 

 45°) 9°°) 1 35°j ^'^d 1 80°. The figures on each side of the 

 trace represent the total revolutions of each screv/, and 

 the seconds marked denote the time occupied in passing 



Fig. 9. — Scale, 1 inch 



everything else disposed to trust to the chances and 

 judgment of the moment when manoeuvring the ships 

 in a fleet. What was lost by failure to pursue the 

 experimental method was not seen, and when I state 

 clearly that if the experimental method could have been 

 persevered in and developed, we should not have lost the 

 Victoria and Sir George Tryon, my views are scarcely ap- 

 prehended by the Navy. I cannot enter upon this matter 

 here, though I shall presently make a remark on it which 

 will then be understood. I must conclude my paper by 

 setting forth some of the results which have been obtained 

 by the experimental method. 



In the first place it seems made out that every im- 

 provement in the method of measuring manoeuvring 



NO 1 260. VOL. 49] 



over each " octant." The accuracy of the turn is apparent 

 to the eye, and while the space measurements in no case 

 vary more than 60 feet from the mean, the time measure- 

 ments do not vary more than five seconds from the mean, 

 and that is out of a total of 220 seconds. 



To the figure is added a trace of the Edinburgh's 

 powers of reducing the size of her arc and her speed over 

 it, by reversing both engines full speed, as simultaneously 

 as possible with the movement of the helm. 



Fig. 9 traces a path which is the mean of three turns 

 made by H.M.S. Dreadnought at 10-9 knots speed with 

 32° of helm, where the apparent variations in tne path 

 seem to be greater. But the space variations here are 

 never more than 74 feet from the mean, while the times 



