METEOROLOGY. 



533 



no part in intensifying the coloring. The long 

 continuance of the matter in the atmosphere 

 agrees with experimental determinations of 

 the rate at which smoke settles in atmospheric 

 air. This conclusion is in substantial harmony 

 with the conviction expressed by Mr. A. W. 

 Claydon in the " Journal of the Royal Meteoro- 

 logical Society," that vapor played the principal 

 part, and the other eruption-products only a 

 subordinate one, in the coloration. The phe- 

 nomenon called Bishop's Ring (see " Annual 

 Cyclopaedia," 1885, article ''Meteorology") 

 is also ascribed by Ricco to the eruption of 

 Krakatoa. He supposes that it was caused by 

 the refraction produced by a peculiar conden- 

 sation of vapors into extremely minute parti- 

 cles. The red twilight phenomena differ from 

 this ring in that they were not the effect of 

 refraction, but of a selective transmission, by 

 a well-known and common property of the at- 

 mosphere, of the less refrangible rays. 



Storms. The storm of the llth, 12th, and 13th 

 of March, commonly known as the " Xew York 

 Blizzard,'' was one of the most severe ever ex- 

 perienced on the Atlantic coast of the United 

 States. As described by Prof. AVinslow Upton, 

 in the " American Meteorological Journal," it 

 was peculiarly characterized by the rapidity 

 with which its energy was developed, and by 

 the extreme precipitation that accompanied if, 

 principally as snow. West of the seventy-second 

 meridian, the precipitation was almost wholly 

 snow, piled up in immense drifts, while east 

 of this meridian it was rain and snow mixed. 

 The region in which it prevailed extended, on 

 land, from the neighborhood of Cape Hatteras 

 to the southern part of Massachusetts. The 

 district in which it raged with unmitigated vio- 

 lence included Xew Jersey, southeastern Xew 

 York, Block Island, and southern Xew Eng- 

 land. Through the latter territory snow fell 

 to an estimated average depth of forty inches, 

 while it was massed so irregularly in immense 

 drifts that it was almost impossible to measure 

 it ; railroads were blockaded ; telegraphic com- 

 munication was stopped; shipping along the 

 coast was exposed to great danger; many lives 

 were lost from exposure ; and the city of Xew 

 York was cut off from all communication with 

 other places, except through the Atlantic 

 cables. According to Gen. Greely's summary 

 of the history of the storm, the storm-center 

 was first noticed in the Xorth Pacific on March 

 6, whence it passed southeast from the Oregon 

 coast to northern Texas by the 9th. An ex- 

 tended trough of low pressure, having two dis- 

 tinct centers, was gradually formed, which 

 covered the Mississippi and Ohio valleys on 

 the 10th; and on the llth, according to Prof. 

 Hayden, extended from the west coast of 

 Florida up past the eastern shore of Lake 

 Huron, and far northward toward the southern 

 limits of Hudson Bay. The northern center 

 moved northeastward and disappeared, while 

 the southern center moved slowly eastward, 

 passing off the Atlantic coast near Cape Hat- 



teras. The " cold wave," which followed 

 upon the track of the great trough, as it ap- 

 proached the coast, as explained by Prof. 

 Hayden after examining the reports of sailing- 

 vessels on the ocean at the time, met the warm 

 currents of air from the south, and that ac- 

 companying the Gulf Stream, now trending 

 northwardly after a winter interval of compar- 

 ative quiet; and the difference in temperature 

 of the two air-streams being very great, exces- 

 sive precipitation was the result. The storm, 

 Prof. Hayden says, so far as it has been possi- 

 ble to study it from the data at hand (which 

 need to be re-enforced by fuller ocean reports), 

 furnished a striking and instructive example of 

 a somewhat unusual class of storms. Instead 

 of a more or less circular area of low barometer 

 at the storm-center, there was here a great 

 trough of " low " between two ridges of 

 " high," the whole system moving rapidly east- 

 ward, and including within the arc of its 

 sweep almost the entire width of the temperate 

 zone. u The trough phenomena, as an emi- 

 nent meteorologist has called the violent squalls 

 with shifts of wind and change of conditions 

 at about the time of lowest barometer, are here 

 illustrated most impressively." One thing to 

 which attention is particularly called is the 

 fact that storms of only ordinary severity are 

 likely, upon reaching the coast, to develop 

 increased energy. This is especially so in a 

 storm of this kind, where the isobars are elon- 

 gated in a north and south direction. 



A relation between the velocity of a storm's 

 progress and the extent of the accompanying 

 rain area has been established by Loomis, who 

 found also that the chief part of the rain area 

 was in advance of the storm-center. His ob- 

 servations are confirmed, as to their principal 

 features, by Ley and Abercromby. The last 

 author has shown that the heaviest rain and 

 cloud areas are massed toward the front of 

 rapidly advancing cyclones, while immediately 

 after the passage of the line of minimum press- 

 nre the sky begins to show signs of clearing. 

 It is remarked that in the United States, when 

 the cyclones are moving with unusual rapidity, 

 all the rain and almost all of the cloud area 

 are confined to the front half of the cyclone. 

 Loomis first regarded the rapid advance of 

 cyclones as the effect of excessive rain, but 

 later investigations have shown that the rain- 

 fall is not an essential feature; and certain 

 European observations recorded by Hann sug- 

 L r e?-t that unequal distribution of rain around 

 rapidly moving cyclones is not the cause but 

 the result of the cyclone's advance. H. Helm 

 Clayton supposes that, in cyclones which move 

 very slowly, the air ascends almost uniformly 

 around the center; but when the storms have 

 a more rapid progressive motion, the air in the 

 rear, which has not only to enter but to fol- 

 low the cyclone, is more retarded by friction 

 than the air in front, and hence does not enter 

 the cyclone so freely, so that the formation of 

 cloud and rain iu the rear is retarded ; while 



