20 Prof. J. Joly on Scientific 



circumstance may be such that the iast factor only — luck — 

 determines the result. 



The time has come when a complete .re-consideration of 

 the whole matter in the light of modern advances in 

 signalling is desirable if not indeed imperatively necessary. 

 Not that existing rules need be abrogated. In close traffic 

 these may well prove essential, especially when small 

 coasting craft are concerned. Nor are the modern methods 

 and the older ones mutually exclusive. The chief danger, 

 however, is really in the ocean routes where high speeds 

 must be maintained and the risk taken. There is little doubt 

 that with the compulsory use of such methods of signalling 

 as are now available high speeds could be maintained and very 

 little risk remain. It is irrational to suppose that educated 

 officers who have been trained in far more difficult 

 navigational methods could not use the methods we have to 

 consider. The actual taking in of the signal will probably 

 always fall to the wireless operators on board : men who hold 

 certificates of proficiency in dealing with such matters. 

 Alone the interpretation of the signals lies with the Officer 

 of the Watch. And as a fundamental regulation the Board 

 of Trade would require continuous watch in the wireless room 

 on all ships during thick weather. 



With the advent of wireless telegraphy at sea — due in the 

 first instance to Admiral Sir Henry Jackson — the sailor 

 inherited a means of speech which is available in almost 

 every state of the weather. And in submarine signalling yet 

 another mode of communication is open to him, whereby 

 ship may speak with ship over distances from 6 to 20 or 

 more miles in all weathers. Directions may be determined 

 approximately by both these methods of intercommunication. 

 But wheu the problem of avoiding collision in all circum- 

 stances is fully considered it will, I believe, be recognized 

 that determination of distance — that is, the distance between 

 the vessels — is an essential element for safety. 



And this brings us back to synchronous signalling as the 

 only means whereby distance from ship to ship can be safely 

 determined. 



There is no doubt that the combination of submarine 

 sound signal and wireless signal is the most reliable one 

 available. True, the sensitiveness is no more than will 

 determine the distance to the half-knot although the quarter- 

 knot may be estimated. Practice would do a great deal in 

 such a matter, as everyone who has observed small time 

 intervals in the laboratory soon finds. And it is also to be 

 remembered that we are dealing with ships moving at 



