WIRELESS TIME SIGNALS. 273 



the same thing happens, but the making and breaking of r 

 is almost simultaneous, and we hear a very short sharp dot. 

 At 5, 6, and 7 r cannot get through and we hear nothing. 

 Real coincidence occurs between 4 and 5, and we may make 

 a rule to take either, provided we adopt the same rule at 

 both A and B. It may perhaps be as well to point out that 

 the shortening of the r signals in this way is quite different 

 from the (unsuccessful) attempt to send short sharp dots 

 by shortening the duration of key-closing at the transmitter. 

 In our case the signal may normally be of any duration, 

 and we do not interfere with it until it actually begins to 

 sing. Then our clock automatically cuts it out. In prac- 

 tice we have not yet had an opportunity of testing the 

 method over any great distance. We have, however, taken 

 advantage of some signals sent by the Riefler clock at 

 Adelaide (about 700 miles). The determination of coinci- 

 dence was found to be a very simple matter and quite free 

 from strain. It is far more easy to concentrate the atten- 

 tion upon one series of signal dots, and ascertain when they 

 cease, than to determine the moment of coincidence of two 

 series, and requires no special training. We occasionally 

 obtained the assistance of friends who had no experience 

 of time observations, and their determinations of the exact 

 moments of coincidence always agreed with our own. 



Incidentally a few side issues may be worth glancing at. 



(1) It is obvious that one transmitting station, where 

 possible midway between A and B, is preferable to two. 

 We may then feel pretty certain that the arbitrary signals 

 reach A and B practically simultaneously. 



(2) In Australia the spark and crystal system still holds 

 sway, and we understand that it is also in use in England 

 and France. Through the courtesy of Mr. Ormiston, 

 an American operator, we have been introduced to the 

 arc system, and have been so fortunate as to obtain one of 



R— December 6, 1916. 



