Show BROKEN WIRE how the telegraph operator tells where the Is located perhaps the greatest of all mysteries to the uninitiated about telegraphy is the fact that when a wire is broken or damaged the operator sitting in his office can tell exactly where the accident has occurred the explanation however is very simple it requires force to send electricity through ci wire just as it does to pump water through a hose the longer the wire is alie greater is the force required this force is measured but instead of calling it pounds as in the measuring the pressure in a boiler electricians call the units of electrical force ohms suppose a wire between two offices is miles long and that on a stormy night it gets broken somewhere the knows that when the wire was sound it takes just 2000 ohms to send a current through or 14 ohms per mile he now finds that he can send a current only ohms lie divides by 14 and finds that the break in the wire is 50 miles from his end when the wire is under ohp sea a curious thing happens the electricity decomposes the sea salt and a new salt is formed on the broken ends of the wire and until that is cleared away by what is called a zinc current acting tor ten or twelve hours no measurement can be made |