■i8 A. a Twining on the Earthquake of October, 1870. 



These impressions and recollections would often give durations 

 more than double, in some instances, of the like in other instan- 

 ces. Taking, however, the most trustworthy, and allowing to 

 the others a weight proportioned to their value, under the cir- 

 cumstances, the first shock was found to have continued througli 

 about nine seconds, the second through about eleven seconds, 

 and the interval about five, — ^making, altogether, twenty-six 

 seconds. The time of each double vibration — that is both to 

 and fro — was concluded to approximate to a second and one- 

 third, — although, so far as mere numbers were concerned, the 

 ' approved not more than one second, 



re generally i 

 The precise 



of day will be referred to far- 

 tner on. it is remarkable that motions which were not even 

 noticed, ordinarily, by persons in basement stories or in tne 

 streets, should have produced in most of those who felt them 

 nausea or dizziness or other affections, according to the temper- 

 ament of the individual. 



A careful comparison of the various newspaper paragraphs 

 which have come to hand — nearly forty in number — makes it 

 clear that the general phenomena were everywhere the same. 

 Every where there were two shocks experienced of a few seconds 

 each, and a brief interval. These are about as variously stated 

 in duration by the newspapers as the same were stated by Qu- 

 ferent observers at New Haven : — thus, at Troy 15 to 20 seconds , 

 in all, at Montpelier 30, at Cleveland 15 to 30, the prevalent 

 authoritv being for the latter, at Boston 18 to 30, at Brunswick, 

 Me., 30 "to 40, at Cincinnati 30 and less, at Hartford 20 to m, 

 at Cornell University, Ithaca, three shocks of 15 seconds each-- 

 the three being too exceptional among the mass to be credited, 

 and having but one other parallel, that is, Brooklyn. At Har- 

 vard College Observatory the duration of tremor was from 8 to 

 15 seconds by the estimate of different observers, — two shocks 

 with a continuous tremor between, and the component oscilla- 

 tions 40 in a minute according to observer W. A. Rogers. At 

 East Saginaw, Mich., the first shock is described as 10 seconds, 

 then an equal interval, then a second shock of 10 seconds. A 

 very few of the statements are so abnormal, one or two in their 

 brevity (one or two seconds) and about as many in their length 

 (two or three minutes), that no weight can be accorded to them- 

 On the whole, the entire duration — ^26 seconds— at New Haven, 

 is confirmed as having been about the duration in all other 

 places observed — ^a uniformity probable in itself In one io' 

 stance the oscillations are spoken of as four or five in a second, 

 and as being like tlie motions of a boat, — also in one other (at 

 Keene) they are described as having been vertical. 



Respecting the relative amount of disturbance at different 

 places, the sensations experienced by individuals would be but 



