SCIENCE AND PRACTICE. 407 



The value of x, divided by y, according to the above, which 

 takes a form, -, very convenient in application, is 

 j_ f~r~ 



T := V v 



Each of these methods depends upon a similar measurement 

 from each end of the cable, and this requires, of course, the 

 communication of the results of the observations from one 

 station to the other. It is, however, possible to calculate the 

 position of the fault with the data given, by the determina- 

 tions made at either one of the stations alone. 



The two determinations made by station A are expressed 

 in the equations 1) and 3), while 5) is an equation which 

 follows from knowing the value of I beforehand. 



From these three equations we obtain 



x = r 



and 



8 = (B - r) + >/(R-r)(f r) 

 in units of resistance. In knots they are 



and 



From the two measurements made by B equations 2) and 4) 

 with the general equation 5), we have in units 



x = (I /) H 

 y = r' ^(E r )(l r ') 

 and 



The value in knots, L x and Ly, being, as before, these 

 divided by w, the number of units resistance in a knot at the 

 same temperature. 



