Forecasting the Weather and Storms 257 



night was clear and that good observa- 

 tions were secured, but that a severe 

 northeaster began the next morning. 

 He then sent out many inquiries to 

 stage stations, and learned that at all 

 places southwest of Philadelphia the 

 storm began earlier, and that the greater 

 the distance the earlier the beginning, 

 as compared with its advent in Phila- 

 delphia. Northeast of Philadelphia the 

 time of beginning was later than at that 

 city, the storm not reaching Boston 

 until twelve hours after its commence- 

 ment at Philadelphia. 



Franklin's analogy of the water is all 

 right so far as it goes. But if, instead 

 of the canal, he had imagined a broad 

 ocean, and in place of the gate he had 

 located a maelstrom a hundred miles 

 wide in the center of the ocean, toward 

 which the waters within a circle a thou- 

 sand miles in diameter were moving, 

 first slowly and directly toward the 

 center, then with accelerating velocity 

 and increasing deflection to the right of 

 the center, and finally faster and faster 

 as they drew near and gyrated with 

 fearful speed about the orifice down 

 which they must plunge, he would have 

 gained a clearer idea of the motions of 

 the air in a large cyclonic storm, except 

 that to make the analogy perfect it is 

 necessary to invert the maelstrom and 

 have the upper surface of the ocean face 

 downward upon the land to represent 

 the atmosphere, and then the maelstrom, 

 with its vast system of in- flowing cur- 

 rents, must have a movement of transla- 

 tion eastward. 



The northeast hurricane that swept 

 the region from Boston to Philadelphia 

 was caused by the suction exercised by 

 a cyclonic storm advancing from the 

 southwest, which drew the air rapidly 

 from Boston toward Philadelphia, while 

 the source of the attraction — the center 

 of the cyclone — was several hundred 

 miles to the southwest of the latter 

 place. The velocity of the northeast 

 winds increased as the center of the cy- 



clone came nearer and nearer, until the 

 winds reached the force of a hurricane. 

 When the center of the storm reached 

 the vicinity of Philadelphia the winds 

 suddenly became variable and light, and 

 as the center of the disturbance passed 

 the winds arose as quickly as they had 

 subsided, but with this difference : they 

 now blew from some westerly point in- 

 directly, or spirally toward the center 

 of the storm that was passing eastward, 

 and diminished in force as the center 

 gained distance. 



Had the telegraph been in existence 

 in Thomas Jefferson's day he doubtless 

 would have conceived the idea of fore- 

 casting the weather. In conjunction 

 with his friend, James Madison (after- 

 ward Bishop), he conducted a series of 

 weather observations, which were be- 

 gun in 1 77 1 and continued during the 

 stirring times of the Revolution. Madi- 

 son was near the sea, at Williamsburg, 

 the colonial capital of Virginia ; Jeffer- 

 son was at Monticello, 120 miles west. 

 They took simultaneous observations 

 for several years, until the British ran- 

 sacked Madison's house and carried off 

 his barometer. By comparing observa- 

 tions they discovered that barometric 

 and thermometric changes occurred at 

 Monticello three or four hours before 

 they did at Williamsburg. 



THE BEGINNING OE THE AMERICAN 

 WEATHER SERVICE 



Although American scientists were 

 the pioneers in discovering the progress- 

 ive character of storms and in deter- 

 mining the practicability of forecasting 

 the weather, the United States was the 

 fourth country to give legal autonomy 

 to a weather service. But it would re- 

 quire an international service, embrac- 

 ing all the countries of Europe, to equal 

 the service of the United States in ex- 

 tent of the area covered. Furthermore, 

 forecasts for the countries of western 

 Europe can never cover the time in ad- 

 vance or attain the accuracy of those 



