The current for energizing the sending apparatus is taken from the lines of the _Potomac Light and Power Company_; this runs an electric motor of 200 horse power which in turn drives a 100 kilowatt alternating current generator; the current from the latter flows through a transformer which raises the pressure of it to 25,000 volts. Next a battery of _compressed air condensers_ are charged with this high voltage current and this is discharged by a rotating spark-gap. This spark-gap has a wheel, on the rim of which is set a number of metal points, or _electrodes_ as they are called, and around them are an equal number of fixed metal points or electrodes. When the wheel revolves sparks are made only when the electrodes on the wheel and those that are fixed around it are exactly in a line. Now instead of a few big sparks taking place every second, a thousand smaller ones occur in a second and this makes a whistling sound which is heard by the operator who is _listening in_ at the distant station. The high frequency currents set up by the spark-gap then surge through an _oscillation transformer_ which increases its pressure and finally into and through the aerial wire system where they are damped out in long electric waves. The Morse telegraph key is placed in the receiving room and it works a _control switch_ in the sending room. The control switch breaks up the current that flows from the generator into the transformer into dots and dashes. The receiving instruments have both _electrolytic_ and _crystal detectors_, the other parts being made up of the usual variable condensers, tuning coils and oscillation transformer and head-phones. Well, at last everything was all ready for the final company test and I was mighty glad of it for things were getting very much on my nerves. A cableless station is altogether too big and cold-blooded a proposition for a fellow who likes a little excitement once in a while. The Navy Department had fitted out the cruiser _Salem_ with a sending and a receiving apparatus exactly like that of the Arlington station except it was very much smaller. On February 13, 1913, the _Salem_ sailed from the League Island Navy Yard at the mouth of the Delaware River for the Mediterranean Sea so that the official tests of the Arlington station could be made. The letter _D_ was used for the test signals and we sent these out from Arlington for 15 minutes each time before the messages were transmitted. Officials from the Navy Department gave us the messages to send and we were allowed under the terms of the contract to repeat each message three times to make sure the _Salem_ got it, but no more. The _Salem_ then followed by sending the test signal _D_ and after this she sent four messages which the Captain gave her operators. This exchange of signals and messages was made twice a day throughout the _Salem’s_ voyage across.