250 



EARTHQUAKES. 



E 



EARTHQUAKES. Northeastern America, 

 from New Brunswick to Iowa, and from the 

 river St. Lawrence to Cincinnati and Rich- 

 mond, experienced the rare visitation of an 

 earthquake shock, October 20th. A larger 

 area may have been affected, but within the 

 boundaries mentioned the effects were such as 

 to cause the phenomenon to be noticed and re- 

 ported upon. Although occurring at an hour 

 of the forenoon when most people are awake 

 and alert, the shock was not remarked by 

 great numbers who were out of doors at the 

 time, or living in strongly-constructed build- 

 ings. In its greatest manifestations, as re- 

 ported, it was but a slight affair, which would 

 have caused little or no comment in Central 

 America, South America, or other countries 

 commonly troubled by earthquakes. The in- 

 terest of the event consists in the fact that the 

 region disturbed has had but few, if any, such 

 wide-spread shakings within the memory of 

 man. In great cities, like New York, where 

 there are many tall buildings, the earthquake 

 was plainly perceptible, and caused much 

 fright to their occupants. "We give some il- 

 lustrations, from the New- York papers, of the 

 character and effect of the shock in that city. 



At Connor's six-story type-foundery, corner 

 of Duane and Centre Streets, the upper rooms 

 shook so that the work-women were terrified 

 and rushed into the street. But at the large 

 establishment of Lorillard & Co., tobacco- 

 nists, also on Centre, corner of Chambers, 

 no shock was noticed. At Frank Leslie's 

 newspaper-office, in Pearl Street, near Broad- 

 way, a vibration was remarked by all pres- 

 ent; a large glass chandelier swayed to 

 and fro, the pendants rattling against each 

 other ; and the compositors fled to the street 

 for safety, exclaiming that the building was 

 about to fall. They noticed two shocks, of 

 about (estimated) twenty -five seconds' dura- 

 tion each, with an interval of ten seconds. At 

 Lord & Taylor's, Grand Street, the fourth 

 floor was somewhat shaken, and one woman 

 employed there ran to a window and jumped 

 to the roof of an adjoining shed, while anoth- 

 er fainted from alarm. The twelve hundred 

 children at the Public School in Fourteenth 

 Street, near Second Avenue, were almost 

 panic-stricken, and teachers had much diffi- 

 culty in preserving order, but all made their way 

 to the street uninj ured. Glasses and bottles were 

 thrown from a sideboard at No. 15 East Broad- 

 way. Engravers and printers on the upper 

 floors of the American Agriculturist office 

 felt the shock very distinctly. One of them 

 suffered from nausea as soon as the wave 

 passed. The gas-fixtures vibrated considera- 

 bly. Persons tenanting upper-story rooms 

 at the Astor House, and Metropolitan, St. 



Nicholas, and other hotels, noticed the shock, 

 and were unpleasantly affected at the stomach. 

 But in other high buildings in the city noth- 

 ing was known of the earthquake until the 

 evening papers reported it. In Brooklyn, 

 Hoboken, and other places in the vicinity of 

 the city, the shock produced about the same 

 effect in some localities as those already de- 

 scribed, while in other parts of the same 

 cities, towns, or villages, it did not arrest 

 attention. Observers in this neighborhood 

 agree in maintaining two separate shocks, and 

 that the oscillatory movement was from north- 

 northeast to south-southwest. 



This earthquake is the subject of a very 

 complete investigation in the American Jour- 

 nal of Science and Arts, by Mr. Alexander C. 

 Twining. He has collected all the data about 

 it which could be obtained. Before proceed- 

 ing to give details, he remarks that the move- 

 ment of the earth was not level but rocking, 

 and that this sensation is plainly indicative 

 quite as much of a vertical displacement 

 as of any alternations of inclination in the 

 earth's surface after the manner of a wave, 

 and a consequent vibratory condition of per- 

 sons and objects. In estimating the dura- 

 tion of the two shocks, and the interval 

 between them, he employed means to ascer- 

 tain (at New Haven) the informants' mental 

 impressions and recollections, applying to them 

 his own measurement as to time. These would 

 often give durations more than double of 

 those in other instances. Taking, however, 

 the most trustworthy, and allowing to the 

 others a weight proportioned to their value, 

 he found the first shock to have continued 

 about nine seconds, the second about eleven 

 seconds, and the interval to have been about 

 five seconds. Mr. Twining says : 



A careful comparison of the various newspaper 

 paragraphs which have come to hand nearly forty 

 in number makes it clear that the general phe- 

 nomena were everywhere the same. Everywhere 

 there were two shocks experienced, of a few seconds 

 each, and a brief interval. These are about as vari- 

 ously stated in duration by the newspapers as the 

 Bame were stated by different observers at New 

 Haven : thus, at Troy fifteen to twenty seconds in 

 all, at Montpelier thirty, at Cleveland fifteen to 

 thirty, the prevalent authority being for the lat- 

 ter, at Boston eighteen to thirty, at Brunswick, 

 Me., thirty to forty, at Cincinnati thirty and less, 

 at Hartford twenty to sixty, at Cornell University, 

 Ithaca, three shocks of fifteen seconds each the 

 three being too exceptional among the mass to be 

 credited, and having but one other parallel, that is, 

 Brooklyn. At Harvard College Observatory the 

 duration of tremor was from eight to fifteen seconds 

 by the estimate of different observers two shocks 

 with a continuous tremor between, and the compo- 

 nent oscillations forty in a minute according to ob- 

 server W. A. Rogers. At East Saginaw, Mich., the 

 first shock is described as ten seconds, then an equal 

 interval, then a second shock of ten seconds. A 



