76 SOME COMPARISONS RELATING TO 



given as 7 .i per cent, the efficiency of the Cyclops would appear to be about 4.8 per cent. 

 The only thing to do was to write to the Navy Department and find out the solution of the 

 problem. There was absolutely no question in my mind but the solution existed, it only being 

 a matter of finding this explanation. If these figures were correct, then some very grave 

 fault must exist in the Cyclops. 



I wrote to the Navy Department and the following letter was received : — 



File So. 160340-639-D 



Navy Department, 

 Bureau of Steam Engineering, 

 Washington, D. C, July 22, 1915. 

 Sir: — The Bureau has no definite knowledge of the source of Lieutenant Robinson's 

 data, but presume they were obtained from the Cyclops. Examination has, however, been 

 made of the logs of that vessel, and the following figures obtained for the speeds noted in 

 your letter: — 



10 knots 71.5 tons. 



1 1 knots 78.5 tons. 



12 knots 86 tons. 



13 knots 94.5 tons. 



The above figures are from a number of voyages. The Bureau has no information as 

 to where Lieutenant Robinson's figures were obtained, but as he was engineer officer of the 

 Jupiter, they are presumably from nms made by that vessel. 

 Very respectfully, 



(Sgd.) R. S. Griffin, 

 Engineer-in-Chief, U. S. N., 

 Chief of Bureau. 



The comparison between the Jupiter and the Cyclops according to Lieutenant Robin- 

 son's paper was: — 



The report of the trial published by Lieutenant Robinson gives the coal consumption of 

 the Jupiter as 54.08 tons per day at 10.01 knots speed and not as 50.5 tons. The letter 

 from the Navy Department which is published above gives the correct figures for the 

 Cyclops. 



Another reason for doubting the supremacy of the turbo-electric type of plant is found 

 on page 190 of last year's Transactions: — "These propellers (the Jupiter's) were designed 

 by Capt. C. W. Dyson, U. S. N., and show a remarkable efficiency, giving the same speed as 

 her sister ship on from 300 to 800 less horse-power." 



