50 PROCEEDINGS OP THE AMERICAN ACADEMY 



in its brief duration. The radially outblowing wind, of destructive 

 strength, at and a little south of the apex of the storm-curve, was aa 

 invariable accompaniment of the storm for at least two hundred miles 

 aloD"- its path. It was doubtless felt before the storm reached Henson- 

 ville, and after it crossed Massachusetts Bay and ran out to sea beyond 

 Cape Cod ; it would be interesting to obtain a record of it in these 

 at present unknown parts of its path, to see how nearly they would 

 fall in with the observations here charted. A rapid fall of tempera- 

 ture accompanied the fall of the rain, as will be further shown below. 

 The Catskill Mountains, over 2,500 feet high, the Hudson valley, the 

 mountains of western Connecticut and Massachusetts, with summits 

 up to 2,500 feet, and the Connecticut valley, were all traversed by 

 the storm, without exerting any definite effect on its course or velocity. 

 Whatever the mechanism of the storm may be, it is evident that it is 

 at work chiefly at a considerable altitude, and that it is borne along 

 by the general winds in which it is engendered, while only its more 

 remote effects reach the ground. 



A " composite portrait " of the surface effects of this storm is pre- 

 sented in Figure 6. It is constructed by throwing all the observations 

 (except certain ones in S. E. Mass.) into their proper place with 

 respect to the rain-front and middle-path.* The spaces between the 

 curved lines represent intervals of fifteen minutes before or after the 

 time of rain-beginning, and hence correspond to a distance of about 

 twelve miles, as the velocity of the storm was forty-eight miles an 

 hour. All observations of a single station fall on a line to one side 

 of and parallel to the middle-path, and at their appropriate interval 

 before or after the rain-front. The temperatures are given by num- 

 bers, showing degrees Fahrenheit. The winds are marked by arrows 

 whose feathers increase with their velocity; arrows without bai'bs 

 represent winds when force but not direction was given. The first, 

 loudest, and last thunder are indicated by Tj, T, and Tg. A few 

 lightning strokes are marked by L. The condition of the sky is 

 roughly shown by black or white crescents, which mean clouds or 

 clear sky in the direction of their convex curve. The dui-ation of the 

 rain is marked by black lines. The portrait as thus constructed there- 

 fore gives a graphic generalization of the average relations among all 

 these features of the storm.f In this case the material is insufficient 

 for a wholly satisfactory diagram ; but a good purpose is served in 



* See Proceedings of the American Academy, 1885-86, xxi. 346. 

 t Figures 5 and 6 are reprints from Science, May 14, 1886. 



