SIGNAL SERVICE. 



807 



stretch of accurate prevision (nnd often it must 

 In- done with a very tew minutes for delibera- 

 tion) to deride at what points on the coast the 

 storm-wind will strike with danirenms cfiVct. 



I'l-artically fatal to the value of his warn- 

 ings if they are found to be superfluous, since 

 iu that case they cense to command the atten- 

 tion of seamen. Nor, for like reason, must 

 they ho displayed too late; nor yet too early, 



'iey should interfere with the movements 

 of vessels which might run out of the danger- 

 ous vicinity before the storm can reach them. 

 Thus the perplexing questions which spring up 

 at every display of the signals lend to this part 

 of the Service duty the intensest interest. No 

 such work had ever been undertaken in this 

 country when the Signal Service was organ- 

 ized ; and though maritime storm-signaling on 

 a small scale had been tentatively prosecuted 

 in England by Admiral Fitzroy, his labors 

 were held by his own Government of ques- 

 tionable success, and at his death in 1866 the 

 experiment had been abandoned by it as pre- 

 mature, if not utterly hopeless. 



On the organization of the United States 

 Weather Service in 1870, the Chief Signal Of- 

 ficer began with great caution to prepare for 

 this difficult and delicate part of his arduous 

 task; and on the 24th of October, 1871, the 

 display of signals on the seacoasts and lakes 

 commenced. The order regulating this dis- 



play contemplated that the warning should be 

 sent only to stations at which a storm-wind 

 having a velocity of twenty-five miles un hour 

 would occur. As the anemometer at every 

 station registers the wind's velocity for every 

 hour, it is easy to ascertain whether any sig- 

 nal has been justified. Every such display is 

 carefully followed up by the otfice, and the 

 result "justified" or u not justified " i- re- 

 corded, as reported by the observers hoisting 

 the signals by telegraphic order from the Chief 

 Signal Officer. 



The cautionary signals are of two kinds : 1. 

 Those premonishing dangerous winds to blow 

 from any direction ; 2. Those premonishing 

 off-shore winds, likely to drive vessels out to 

 sea. Both kinds are needed by mariners as 

 the storm - centers approach or depart from 

 a maritime station. The first, distinctively 

 termed the " Cautionary Signal," consists of a 

 red flag with a black square in the center, for 

 warning in the daytime, and a red light by 

 night. The second, or " Cautionary Off-Shore 

 Signal," consists of a white flag with black 

 square in the center shown above a red flag 

 with square black center by day, or a white 

 light shown above a red light by night, indi- 

 cating that, while the storm has not yet passed 

 the station, and dangerous winds may yet be 

 felt there, they will probably be from a north- 

 erly or westerly direction. The display of 



THE CAUTIONARY SIGNAL-FLAG, A8 BEEN IN NEW YORK HARBOR. 



either signal, however, is always intended to 

 be cautionary, and calls for great vigilance on 

 the part of vessels within sight of it. 



The Chief Signal Officer's report for the 

 year ending June 30, 1879, states that, in that 

 year, 2,573 such signals had been displayed in 

 anticipation of 96 dangerous storms assailing 

 the lake and ocean coasts of the United States ; 



and that of the number of u cautionary" sig 

 nals displayed, 79 '8 per cent, have been after- 

 ward reported as justified by dangerous wind- : 

 while of the number of " cautionary off-shore " 

 signals displayed, 93*9 per cent, have been af- 

 terward reported as justified. According to 

 the rules of the office, a signal is set down as 

 not justified unless it is shown after the die- 



