Page:The National geographic magazine, volume 1.djvu/66

 the instruments themselves vary greatly in quality, and while some of them may have been compared with standards very recently, there are others whose errors are only approximately known. Moreover, when a vessel is pitching and rolling in a storm at sea, in imminent danger of foundering, it is, of course, impossible to set the vernier of the barometer scale and read off the height of the mercury with very great precision. It will thus be readily understood that the many hundreds of observations carefully taken and recorded for the Hydrographic Office by masters of vessels are necessarily more or less discordant, although the results obtained rest on the averages of so many reports that the probable error is always very small. An exhaustive study of reports from vessels at various positions along the coast, from the Straits of Florida to Sandy Hook, together with the records of the coast stations of the U. S. Signal Service, indicates a continuous eastward movement of the trough of low barometer during the night, accompanied by a rapid deepening of the depression. All along the coast we have the same sequence of phenomena, in greater or less intensity, according to the latitude of the vessel, as we noticed here in Washington that Sunday afternoon, when the warm southeasterly wind, with rain, died out, and after a short pause a cold northwesterly gale swept through the city, piling up the snow in heavy drifts, with trains belated or blockaded, and telegraphic communication cut off almost entirely with the outer world. It was a wild, stormy night ashore, but it was ten-fold more so off the coast, where the lights at Hatteras, Currituck, Assateague, Barnegat, and Sandy Hook mark the outline of one of the most dangerous coasts the navigator has to guard against. To bring the scene vividly before the mind would require far more time than I have at my disposal, and I can only regret that I cannot quote a few reports to give some idea of the violence of the storm.

By means of a careful comparison of many reports, it is evident that although the general trough-like form of the storm remained, yet another secondary storm center, and one of very great energy, formed off shore, north of Hatteras, as soon as the line had passed the coast. It was this center, fully equal to a tropical hurricane in violence, and rendered still more dangerous by freezing weather and blinding snow, which raged with such fury off Sandy Hook and Block Island for two days,—days likely to be long memorable along the coast. Its long continuance was probably due to