THE CLIMATOLOGY OF THE UNITED STATES. 27 



lantern by night is called the cautionary signal and denotes 

 that a storm of considerable energy is approaching and 

 that the wind will probably blow at the rate of twenty-five 

 miles or more per hour. In this connection it should be 

 noted that when the wind blows twenty-five miles per hour 

 in Boston it may blow forty miles per hour off" Cape Cod ; 

 therefore when a person in the city considers the warning not 

 justified he should remember that it is displayed for the 

 benefit of mariners, owing to the large number of vessels 

 trading between ports scattered over an immense coast line 

 extending from the provinces to the Gulf of Mexico. The 

 displaj'of signals at various points on that line is a matter 

 of interest to a great many people having the care of a 

 large amount of property, and when a very severe cyclone 

 is coming up the coast the signal officer in a port like Bos- 

 ton, for example, not only displays the signal when he re- 

 ceives orders to that effect from Washington, but sends the 

 police boat about the harbor to notify officers of vessels 

 about to leave port of the character of the approaching 

 storm. When the wind is expected to blow very strongly 

 from the west or northwest the cautionary off-shore signal 

 is displayed. This consists of a white flag with a black cen- 

 tre above the red flag already mentioned by day and a 

 white light above the red light by night. The white flag 

 alone indicates a cold wave. Of the display of these sig- 

 nals it may be said that about ninety per cent have been 

 justified. When the wind does not attain a velocity of 

 twenty-five miles per hour within the district the display 

 of the signal is considered unjustified, yet the wind may 

 attain nearly that velocity and so we may consider a larger 

 proportion correct in a general way. The inland weather 

 signals consist of three white flags, one with a red ball, 

 one with a red crescent, and one with a red star denoting 

 respectively higher temperature, lower temperature, and 



