The Great Storm of March ll-lJ^, 1888. 53 



large extent and deepening intensity of the blue tint, where the 

 temperatures are below the freezing point. From, the northwest- 

 ern to the southeastern portion of the chart we find a difference 

 in temperature of more than 80° F. (from below -10° to above 

 70°); the steepest barometric gradient is found to the northwest 

 of Block Island, where the pressure varies 1.80 inches in 750 

 miles (gradient, .036 inch in 15 nautical miles), and .66 inch in 

 126 miles (Block Island to Albany, N. Y.; gradient, .079). 



On the chart for 7 a. m., March 14th, the depression off Block 

 Island has almost filled up, and the stormy winds have died out 

 and become light and variable, with occasional snow squalls. The 

 other storm center has now regained its ascendency, and is situated 

 about two hundred miles southeast from Sable Island, with a 

 pressure about 29.3. The great wave of low barometer has over- 

 spread the entire western portion of the North Atlantic, with un- 

 settled squally weather from, Labrador to the Windward Islands. 

 The area of high pressure in advance has moved eastward, to be 

 felt over the British Isles from the l7th to the 21st of the month, 

 followed by a rapid fall of the barometer as this great atmos- 

 pheric disturbance moves along its circuit round the northern 

 hemisphere. The isotherm of 32° is still south of Hatteras, 

 reaching well out off shore, and thence northward, tangent to 

 Cape Cod, as far as central Maine, and thence eastward to St. 

 Johns, Newfoundland. Great contrasts of temperature and 

 pressure are still indicated, but considerably less marked than on 

 the preceding chart, and the normal conditions are being gradu- 

 ally restored. 



Conclusion. 



The great storm that has thus been briefly described, as well as 

 can be done from the data now at hand and in the limited time at 

 our disposal, has furnished a most striking and instructive exam- 

 ple of a somewhat unusual class of storms, and this on such a 

 grand scale, and in a part of the world where the data for its study 

 are so complete, that it must long remain a memorable instance. 

 Instead of a more or less circular area of low barometer at the 

 storm center, there is here a great trough of " low " between two 

 ridges of " high," the whole system moving rapidly eastward, and 

 including "within the arc of its majestic sweep," almost the entire 

 width of the temperate zone. The " trough phenomena," as an 

 eminent meteorologist has called the violent squalls, with shifts 



