274 



SCIEJS^CE. 



[Vol. VIII, No. 190 



detonation and observed tremor, together suggest 

 that the sound came directly from the earth, 

 either as sonorous vibrations, or as soundless pulsa- 

 tions of such period as to be converted into sound- 

 waves on passing from earth to air, 



2. The principal physical record of the great 

 shock at Ten-Mile Hill is found in the craterlets, 

 or ' sand-spouts,' which there attain maximum 

 size and abundance. They are simple circular or 

 elongated orifices from which water has welled 

 forth with such violence as to flood the entire sur- 

 face over hundreds of acres to depths of from one 

 to two or more feet, to carry out hundreds of tons 

 of the yellow and blue sand overlying the marl- 

 bed, and to spread this sand over scores of acres 

 to depths varying from a fraction of an inch to 

 two or three feet. These crateriform orifices are 

 now surrounded by their solid ejecta in annuli 

 attenuating peripherally, in which the shrinking 

 streams from the dwindling fountains have worn 

 channels and gullies, as shown in fig. I ; and most 

 of them are now filled with water up to within a 

 foot or two of the natural surface. By residents 

 the waters are reported to have gushed forth dur- 

 ing, and for some hours after, the grf at shock, 

 sometimes by jets but generally continuously, to 

 the height of trees ; and, since they sometimes 

 contained sulphurous compounds, they gave out 

 characteristic odors that added much to the terror 

 of the people. The volume of water extravasated 

 was sufficient to flood many of the minor drain- 

 age-ways above even the highest freshet-marks ; 

 and five days after the great shock, water still 

 flowed from some of the craterlets, and yet re- 

 tained the odor of sulphuretted hydrogen. There 

 is no indication that the orifices extend, or that 

 the water flowed from, below the base of thesuper- 

 ficial sands (in which the mean depth of permanent 

 ground water is ten or fifteen feet), either at Ten- 

 Mile Hill or elsewhere ; and, indeed, at the phos- 

 phate-works nearest Ten-Mile Hill, in the immedi- 

 ate vicinity of which both fissures and craterlets 

 occui-, the marl-bed was so slightly disturbed at 

 depths of sixty or seventy feet, that the water 

 slowly percolating into the shafts was neither in- 

 creased nor discolored. Nevertheless, these foun- 

 tains, issuing from a surface fifteen feet above the 

 level of ground water, the flow from fissures here, 

 at Summerville, and to a less extent at Charleston, 

 and the rise of waters in wells in various localities, 

 all point to sudden and considerable contraction, 

 either vertical or horizontal, of the water-bearing 

 sands overlying the marl. ' Sinks ' are, indeed 

 (rarely), associated wuth the craterlets ; but they 

 appear to have been formed after the subsidence 

 of the extravasated floods. 



In the vicinity of Ten-Mile HUl, too, the kink- 



ing and distortion of railway-tracks is most strik- 

 ing. In a number of cases the rails were so bent 

 as to necessitate removal ; the displacement in 

 alignment sometimes reading two feet or more, 

 while that in profile was half as great. It should 

 be mentioned, that, in all personally observed and 

 well authenticated cases of compressive distortion 

 of rails, the kinks occurred in the low-grounds at 

 the bottoms of inclines, and generally in the 

 vicinity of trestle-bridges approached by embank- 

 ments, and that at least a part (and in one case all) 

 of the contraction relieved by the kinking appears 

 to have been caused by the down-hill settling of 

 rails, ballasting, and embankment. Nevertheless, 

 longitudinal fissures in the embankments, and 

 lateral throw of the track, have evidently been 

 produced directly in some cases : and near Ten- 

 Mile Hill a locomotive was derailed (with destruc- 

 tion of life) during the second shock ; but whether 

 by the tremor, or as a result of antecedent dis- 

 placement of the ti'ack, could not be ascertained. 



In general terms, the injury to the few build- 

 ings at Ten-Mile Hill is similar to that exhibited 

 at Summerville, save that the horizontal displace- 

 ment has been greater, chimneys have been more 

 generally overthrown, and the plastering of the 

 ceilings is less seriously, and that of the walls 

 more seriously, cracked and dislodged. 



It is noteworthy, that, between Ten-Mile Hill 

 and Charleston (perhaps three miles from the lat- 

 ter place), there is a considerable area or zone in 

 which the effects of the earthquake are inconspicu- 

 ous : chimneys have seldom been overthrown, 

 buildings are not displaced on their foundations, 

 the foundations themselves are not crushed, and 

 plastering is but slightly injured. Even the tall 

 brick chimneys of the fertilizer- works within the 

 area appear to have escaped injury. 



3. As has already been made known through 

 the daily press, the most conspicuous effect of the 

 seismic disturbance at Charleston was the lateral 

 displacement and overthrow of chimneys, monu- 

 ments, walls, entire buildings, etc. These records 

 of the great earthquake have been examined and 

 noted with care, with the view of applying Mallet's 

 method of determining the origin and paths of the 

 seismic tremors to the region affected thereby. 

 The observations on injured buildings may be 

 briefly generalized.as follows : — 



1. The throwing outward of walls, gables, 

 cornices, copings, etc., is most common in walls 

 facing north, next in those facing south, third in 

 those facing east, and least in those facing west. 

 2. By far the greater .number of overthrown 

 chimneys have fallen either to the north or south, 

 and more to the north than the south. 3. The 

 most seriously cracked walls are those facing east ; 



