ELECTRIC PROPULSION OF MERCHANT SHIPS. 299 



vigor that can easily be relied upon to explain break-downs and general mechanical impair- 

 ments and casualties of almost any magnitude. 



Think of an 8-inch crank shaft being dropped in two in an engine, simply because the en- 

 gine is passing through a critical, perfect steel being exhibited at the fracture. As stated, 

 wherever criticals exist one must look for three things: — First, a source of period; second, 

 revoh'ing moments ; and, third, more or less resilience within the system. To suppress crit- 

 icals all one has to do is to place the criticals and the periods "on an open circuit," as it 

 were ; that is, there must be a break in molecular continuity between the source of the period 

 and the mass moments. 



A magnetic clutch has been recently devised, which promises to provide most perfectly 

 the "open circuit" and thus constitute a complete solution of the problem. The development 

 of this disconnecting clutch is timely, and it is now being installed and is found to completely 

 suppress the serious criticals that exist in the submarine engines. In this instance it consti- 

 tutes a disconnecting clutch taking the place of the normal engine fly-wheel. The driven mo- 

 ments, while they are being fully and powerfully driven with zero slip, are yet driven, through 

 a medium which is such that all torsional molecular concussion is completely open circuited ; 

 in fact, the driven element of the clutch is not brought into any physical contact with the 

 driver. The break in the continuity is complete and thus effectively prevents critical periods 

 from building up or even starting. 



It is believed that a judicious disposition of one of these clutches in the system, either 

 between the gear and the thrust block on the one hand and the turbine on the other, or inter- 

 mediate in a double reduction drive, will insure successful operation of the entire gear sys- 

 tem by completely warding off the tremendous over-stresses coming upon the gear teeth and 

 other parts through the subtle though powerful operation of criticals, torsional concussion, 

 or vibration. 



The President : — Gentlemen, I am sure you will permit me to extend the thanks of the 

 Society to Mr. Emmet for his very interesting paper, which has elicited so much interesting 

 discussion. 



We have now completed our program of technical papers and discussions. Do not for- 

 get that tomorrow morning at 11 o'clock the steamer Chester W. Chapin leaves for the Sub- 

 marine Boat Corporation works; also' that the banquet will be held at the Waldorf-Astoria 

 tomorrow night at seven o'clock. We hope then to have a most happy reunion. 



There being no further business before the Society, I now declare the twenty-seventh 

 m.eeting of the Society of Naval Architects and Marine Engineers as having come to a close. 

 Before formally adjourning, I wish to remind you that the success of this meeting is due in 

 very large part to the earnest and devoted efforts of your secretary and his staff, and I know 

 that you will wish me to extend a very hearty vote of thanks to Mr. Cox and his associates 

 in your behalf. (Applause.) 



I now declare the meeting adjourned sine die. 



