12 4 



THE POPULAR SCIENCE MONTHLY. 



most severe and was the one that did 

 the principal damage. The second 

 shock lasted four seconds, and the third 

 and fourth 6liocks were very light. Pro- 

 fessor Newcorab observed three shocks, 

 the first of which he fixed at 9-53-20. 

 Mr. McGee, after the culmination of 

 the first shock, timed the phenomena, 

 improvising a seismoscope out of a 

 tumbler of water placed on a stand, 

 and a rude seismometer out of the 

 high head-board of his bedstead. The 

 following is the record of his observa- 

 tions : 



"Time of culmination of first shock 

 (seventy-fifth meridian) 9'54£; dura- 

 tion of first shock (estimated), eighty 

 seconds; time of termination of same, 

 9*55 ; time of termination of the slight 

 tremor, 10-00 (several slight tremors fol- 

 lowed but were not timed) ; time of re- 

 commencement of continuous tremors, 

 10 - 08; time of culmination of the sec- 

 ond shock, 10 - 09|; duration of second 

 shock, about thirty seconds; time of 

 termination of second series of tremors, 

 10- 13. The direction of vibration, as 

 indicated by the improvised seismo- 

 scope, was a little north of east, but 

 there was an indeterminate vertical 

 component in the undulation plainly 

 perceptible in the motions of liquids and 

 of articles of furniture. Roughly, the 

 upward impulse in each vibration ap- 

 peared to be one third or one half of 

 the lateral impulse. 



"The rate of vibration was meas- 

 ured on the high, swinging head-board 

 of a bedstead during the second shock, 

 and found to be one hundred and fif- 

 teen or one hundred and twenty per 

 minute. During the second shock the 

 head-board, eight and a half feet high, 

 swung through an arc of from one half 

 to three quarters of an inch. It was 

 estimated that the amplitude of oscilla- 

 tion during the earlier shock was twice 

 or thrice as great." 



Mr. Richard Randolph, civil engi- 

 neer, of Baltimore, gives the time of 

 the first shock as 9v>3.V. The oscilla- 

 tions in his room were emphasized by 



the synchronous beating of some object 

 in his bedroom, which upon examina- 

 tion he found to be the tapping of the 

 door of a wardrobe, and that, he ob- 

 serves, could only be produced with an 

 east-and-west oscillation. To repro- 

 duce the tappings with the intensity and 

 period that marked them during the 

 earth-movement required a movement 

 of half an inch at six and a half feet from 

 the floor, for a complete oscillation. At 

 Rochester, New York, a magnetic storm 

 was observed to be raging all the morn- 

 ing of September 1st. It was observed, 

 at the Signal-Service Office in Washing- 

 ton, that the self-registering wind-vane 

 showed a horizontal mark preceding 

 and subsequent to the shaking, denot- 

 ing a mild, steady breeze, but, for the 

 thirty or forty seconds of most violent 

 shaking, the marks indicated great and 

 rapid agitations of the registering-pen- 

 cil. Captain Vogel. of the steamer city 

 of Palatka, observed at sea, twelve 

 miles off Port Royal, " a terrible rum- 

 bling sensation," which lasted about a 

 minute and a half. There had been a 

 heavy sea from the southeast, but when 

 the rumbling began the wave-motion 

 ceased and the waters remained perfect- 

 ly quiet until the rumbling stopped, 

 when the wave-motion again became 

 manifest. The depth of the water at 

 Charleston has not been greatly af- 

 fected; but, according to Captain Bou- 

 telie, it has been increased by from six 

 inches to a foot. Fainter shocks have 

 been reported from Charleston as oc- 

 curring nearly every day since the 

 principal catastrophe. 



THE BRITISH AND FRENCH ASSOCIA- 

 TIONS. 



The meetings of the British and 

 French Associations this year were suc- 

 cessful from both scientific and mate- 

 rial points of view. The city of Bir- 

 mingham, where the British Association 

 met, provided so well for the accommo- 

 dation and entertainment of its guests, 

 that Mr. Galton, in seconding the usual 



