788 THE POPULAR SCIENCE MONTHLY. 



It will be seen how discovery started from a casual hint based on 

 the observations of a keen and well-trained mind; how it was 

 stimulated in a later observer, who bent himself to the painstaking 

 collation of facts bearing on one special set of phenomena ; how 

 these facts finally warranted him in advancing a hypothesis ; how 

 this hypothesis was opposed and criticised ; how it maintained 

 itself in the face of increasing light ; how more extended observa- 

 tions confirmed it and enlarged its application; how it became 

 the basis of all subsequent investigation ; how it was sustained 

 by the testimony of other observers working along similar lines ; 

 and how to-day it is at the very corner-stone of the meteorological 

 science in America. To this narrative let us turn. 



It may be fairly presumed that the well-known suggestions of 

 Benjamin Franklin, based on the occurrence of a northeasterly 

 storm in Boston shortly after one was noted in Philadelphia, was 

 the first definite contribution to the scientific knowledge of North 

 American storms and their movements of transition. Though 

 that contribution was little more than a speculation, it was nev- 

 ertheless one of those sagacious anticipations of results which 

 marks the true scientific genius. In a letter to Jared Eliot, dated 

 at Philadelphia, July 16, 1747, Franklin says: "We have fre- 

 quently along this North American coast storms from the north- 

 east which blow violently, sometimes for three or four days. Of 

 these I have had a very singular opinion for some years i. e., 

 that though the course of the wind is from northeast to south- 

 west, yet the course of the storm is from southwest to northeast ; 

 that is, the air is in violent commotion in Virginia before it moves 

 in Connecticut, and in Connecticut before it moves at Cape Sable." 

 In another letter to Eliot, dated at Philadelphia some two years 

 later (February 13, 1749-'50), Franklin says : " You desire to know 

 my thought about northeast storms beginning to leeward. Some 

 years ago there was an eclipse of the moon at nine in the evening 

 which I intended to observe, but before night a storm blew up at 

 northeast and continued violent all night and next day; the sky 

 was thick clouded, dark, and rainy, so that neither moon nor stars 

 could be seen. The storm did a great deal of damage all along 

 shore, for we had accounts of it in all the newspapers, from Bos- 

 ton, Newport, New York, Maryland, and Virginia. But what 

 surprised me was to find in the Boston newspapers an account of 

 an observation of the eclipse made there, for I thought as the 

 storm came on from the northeast it must have begun sooner in 

 Boston than with us, and consequently prevented such observa- 

 tion. I wrote to my brother about it, and he informed me that 

 the eclipse was over there one hour before the storm began. 

 Since which I have made inquiries, from time to time, of travel- 

 ers and of my correspondents to northeast and southwest, and 



