198 ELECTRIC PROPULSION OF THE U. S. S. JUPITER. 



low-pressure receiver was about the same as that at the low-pressure turbines of the Utah. 

 Taking the water rate of the Delaware engines for the high and intermediate pressure cylin- 

 ders, also the water rate for the low-pressure turbine of the Utah, and combining the two, he 

 gets an economy of about 9.5 pounds of water per horse-power per hour, which is about as 

 good as can be expected under present practice. He also states that still further improve- 

 ments can be made which would bring the rate down. 



In closing I would like to say that if the same attention had been given to reciproca- 

 ting engines as has been given to turbines there is no doubt but that this type of engine 

 would be a great improvement over those now in use. 



The Chairman: — Is there any other gentleman who desires to discuss the paper be- 

 fore Mr. Emmet replies? 



Commander J. K. Robison, U. S. Navy, Visitor: — ^As an engineer officer in the Navy, 

 I want to say that we subscribe heartily to what Mr. Emmet says. There is not one of us 

 who will ever know as much about the Jupiter as he does. I do not think that there is any 

 use of our knowing so much as that. As he says, ours is not a case of not wanting advan- 

 tages, but it is our principal duty to get things done for us. He says he does not quite un- 

 derstand — I do not think he put it that way exactly — the extreme conservatism of the naval 

 engineer. And I will point out that they have not electrical turbines on locomotives as yet. 

 There is one paragraph in his article as printed, that, it seems to me, indicates somewhat 

 difficulties that we do not yet know anything about, and that we must know before we can 

 subscribe heartily to Mr. Emmet's opinion as stated in the article, and admit the certainty that 

 his scheme is always going to be better than anything else. For instance, this collier is some- 

 times going to have 10,000 tons of coal in it and sometimes not any. What will be the effect 

 of that on your electrical density? What effect will that have on the operation of the motors? 

 Suppose the governor — which is a wonderful governor, and which is completely automatic — 

 does not always function? Suppose it happens to work like the automatic water level regu- 

 lator on the Belleville boiler ? Suppose you have a ship pitching heavily, will that affect your 

 motors at all? As pertaining to our alleged ultra conservatism, we would like to invite the 

 attention of the author, who has done so much for us, to the fact that the Jupiter is a naval 

 collier, and I do not think there are any other vessels equipped with this plan of propulsion. 



The Chairman:—! do not want to shut off the discussion if there is any one who 

 desires to speak. If no one else desires to discuss the paper, we will ask Mr. Emmet to make 

 such replies as he cares to. 



Mr. Emmet:— Mr. Linnard put the question about reversibility. I saw the ship re- 

 verse. She was going about three-quarter speed, possibly, the switch was simply thrown, 

 there was no experiment made to determine time, etc. I do not think there would be many 

 strains, except what might come on the propeller blades, and the conditions are not essen- 

 tially different from those of any other ship in that respect. At least I can see no reasons 

 for there being any difference. 



The question of the relative efficiency of turbines and engines is one that we do not 

 need to discuss here at very much length, because it has been so much talked about, but 

 there are certain underlying reasons why a turbine should be more efficient. It can provide 



