i 



The Great Storm of March H-U, 1888. 41 



collect and utilize all available information, but to be careful and 

 cautious in generalizing from the data at hand, yet this study 

 must be considered as only preliminary to an exhaustive treatise 

 ■ based on more complete data than it is now possible to obtain. 



Four charts have been prepared to illustrate the meteorologi- 

 cal conditions within the area from 25° to 50° north latitude, 

 50° to 85° west longitude, at 1 A. m., Yoth meridian time, March 

 Tlth, 12th, 13th and 14th respectively. Data for land stations 

 have been taken from the daily weather maps published by the 

 U. S. Signal Service, and the set of tri-daily maps covering the 

 period of the great storm has been invaluable for reference 

 throughout this discussion. Marine data are from reports of 

 marine meteorology made to this office by masters of vessels, and 

 not only from vessels within the area charted, but from many 

 others just beyond its limits. The refined and accurate observa- 

 tions taken with standard instruments at the same moment of 

 absolute time all over the United States by the skilled observers 

 of the Signal Service, together with those contributed to the 

 Hydrographic Office by the voluntary co-operation of masters of 

 vessels of every nationality, and taken with instruments com- 

 pared with standards at the Branch Hydrographic Offices immed- 

 iately upon arrival in port, make it safe to say that never have 

 the data been so complete and reliable for such a discussion at 

 such an early date. 



It will not be out of place briefly to refer to certain principles 

 of meteorology that are essential to a clear understanding of 

 what follows. The general atmospheric movement in these lati- 

 tudes is from west to east, and by far the greater proportion of 

 all the areas of low barometer, or centers of more or less per- 

 fectly developed wind systems, that traverse the United States, 

 move along paths which cross the Great Lakes, and thence reach 

 out over the Gulf of St. Lawrence across the Atlantic toward 

 Iceland and northern Europe, Another very characteristic storm 

 path may also be referred to in this connection, the curved track 

 along which West Indian hurricanes travel up the coast. The 

 atmospheric movement in the tropics is, generally speaking, west- 

 ward, but a hurricane starting on a westward track soon curves off 

 to the northwest and north, and then getting into the general east- 

 ward trend of the temperate zone, falls into line and moves off to 

 the northeast, circling about the western limits of the area of 

 high barometer which so persistently overhangs the Azores and a 



