Experimental Electricity 



Practical Electrical Hints for the Amateur 

 Wireless Communication 



Safeguarding Vessels by Radio 



By Annis Salsbury 



ONE wreck a day is said to be the 

 average on the fog-visited Pacitic 

 Coast. Commerce on the Great 

 Lakes, while possible during only half 

 the year, is exposed to dangers inherent 

 in waters visited by dense and persistent 

 fog. Likewise, the Atlantic Coast is not 

 without this menace to navigation, for 

 it runs a close second to the Pacific in 

 the number of its sea tragedies ; the Gulf 

 of Mexico is also frequently blanketed 

 with mist, and there the dangers of col- 

 lision or grounding on coral reef or sand 

 bank are much increased. 



The United States lighthouse service 

 has greatly lessened the death toll of 

 treacherous points, but even a beacon of 

 a million candlepower or the shrillest 

 fog whistle is powerless to combat fog. 

 Sound, unreliable under even the best 

 atmospheric conditions, is refracted and 

 reflected to a marked degree by fog- 

 banks, fog-waves and fog-billows. Fog 

 blots out the bright rays from a light- 

 house as completely as if it were 

 swathed in thickest wool, and the mar- 

 iner who is unfortunate enough to find 

 himself on the sea under these condi- 

 tions, unable to sight a warning beacon, 

 and not trusting fog-siren or booming 

 rocket, flounders about as helplessly as 

 a blind man on a busy street. Fog is 

 without doubt the greatest menace to 

 safety known to navigation, and any 

 means of enabling a mariner to keep his 

 course in fog and to receive timely 

 warning of the proximity of other 

 vessels will relieve ocean travel of its 

 chief danger. 



Scientists in the United States, thor- 

 oughly cognizant of this fact, have for 

 some time been on the trail of devices 

 calculated to overcome this peril of the 

 sea, but not until recently have practical 

 suggestions been put forward for the 

 relief of this age-old menace. 



The "radio compass," which promises 

 to add much to the safety of navigation, 

 has been in use in Europe for several 

 years. It is said that ships have found 

 their way up the river to Hamburg in 

 the densest fog, and that Zeppelins de- 

 pend entirely on stations fitted with this 

 special apparatus during darkness or 

 when the earth and its familiar land- 



Loop oena/:faf 

 nghf ang/ei 



Wiring diagram of the BelUni-Tosi di- 

 rectional receiver 



451 



