September 24, 1886.] 



SCIEJ^CE. 



273 



first, fipsuring of the surface of the earth ; and, 

 second, crushing of foundations and chimneys ; 

 together with, third, shght displacement in dif- 

 ferent directions (and sometimes torsional) of 

 buildings. 



The fissures are irregularly distributed through- 

 out the village and over the surrounding plain. 

 They are generally confined to the high-grounds, 

 but appear to reach maximum abundance about 

 the peripheries of the mbre elevated lands. They 

 are so numerous that sometimes not an acre in a 

 square mile is free from them, and, three days 

 after the great shock, were two inches and less 

 in width, and from four or five feet to as many 

 hundreds in length. From the testimony of the 

 citizens, as well as from the sand and mud stains 

 in their vicinity, it appears that sand-laden water 

 welled from these fissui-es in vast volumes, and 

 continued to flow for some hours, and even, in 

 some cases, days : indeed, water was observed to 

 flow freely from one on the highest ground in 

 Sum'merville up to the fifth day after the great 

 shock during which they are said to have been 

 formed. The local streams were flooded by the 

 water from these fissures, and the floods had not 

 completely subsided a week afterward. The sand 

 and clay washed from them was evidently derived 

 mainly from the uppermost member of the super- 

 ficial deposits, although in some cases the blue 

 sand of the inferior member predominates. These 

 fissures extend in all directions, and occasionally 

 cross and bifurcate at various angles. 



The architecture in Summerville is characteris- 

 tic : the houses are generally of wood, lightly 

 framed, either partially or wholly surrounded by 

 wide verandas, and supported on slender pillars 

 from four to six feet high, either of wood set in, 

 or of brick built upon, the ground ; while the 

 chimneys usually rest on independent brick 

 columns built up from the ground. Few if any of 

 them have suffered injury, save by the great shock 

 of Aug. 31 ; and the injury to the houses them- 

 selves is astonishingly slight, atid generally con- 

 fined to racking of frames, shaking down of plas- 

 tering, and occasional crushing of roofs by falling 

 chimneys. Much injury was done, however, to 

 furniture, which was overturned, tossed about, 

 and in many cases broken. When the supporting 

 pillars were of wood, the buildings have sometimes 

 been displaced, and the entire structure, including 

 the supports, has evidently swung to and fro in all 

 directions, as indicated by the annular crevices 

 surrounding the pillars ; and in such cases the 

 chimneys have almost always toppled over, gen- 

 erally to the north or south, the direction having 

 been determined to a large extent by the slopes of 

 roofs. When, however, the supports were of brick, 



they have been crushed at top and bottom, and 

 fissured obliquely in all directions, as if by blows 

 of a pile-driver, and in some cases the pillars have 

 been driven into the ground, depressing and con- 

 centrically fissuring the surface about their bases. 

 The crushing of the ijillars is invariably greatest 

 beneath the heaviest parts of the building : indeed, 

 in some cases the heaviest pillai-s have completely 

 collapsed, and the buildings are now supported by 

 the piei's beneath the verandas and the lighter 

 parts of the floors. The heavy bases of the chim- 

 neys are simflarly crushed and fissured ; and in 

 numerous instances they, too, have completely 

 collapsed, and all that portion of the chimney be- 

 neath the roof has crumbled down into a mass of 

 loose bricks, sometimes leaving the projecting por- 

 tion intact and in place upon the roof. An ex- 

 ample of the manner in which structures have 

 been crushed vertically with little lateral displace- 

 ment is found in the centre of the village of Sum- 

 merville, where two apparently fragile chimneys, 

 left in position when the building to which they 

 were attached was destroyed by fire years ago, 

 have been crvished and obliquely fissured, but have 

 not been overturned, or displaced laterally to the 

 slightest degree. 



The writer experienced half a dozen or more 

 shocks in Summerville, and heard four or five 

 times that number of detonations. The individual 

 shocks were of very brief duration : the longest 

 observed (and from the testimony of the citizens 

 it appears that this was second in severity only to 

 the great shock of Aug. 31) was over in less than 

 thirty seconds. The motions of furniture, etc., 

 during this shock, were cai-ef uUy noted. It was 

 found, that, during the first two-thirds of its 

 period, the vibration appeared to be dhectly verti- 

 cal ; that a wrenching, torsional motion, turning 

 objects in the direction of the sun, followed ; and 

 that this was succeeded by a few gentle east-and- 

 west rolls. The movements were identical in all 

 the lighter shocks, when of sufficient duration to 

 permit of observation, save in intensity. Ordi- 

 narily, however, the lighter shocks were simply 

 spasmodic quivers of but an instant's duration, the 

 direction of which it was impossible to determine. 

 The shocks were invariably accompanied by sensi- 

 bly simultaneous detonations resembling slightly 

 mufiaed thunder-peals or heavy cannonading, com- 

 monly compared by the older residents, who 

 remembered the bombardment of Charleston, to 

 the booming of ' siege-guns ' a mile or two away ; 

 but the detonations were three or four times as 

 frequent as the tremors. It may be mentioned 

 that no two individuals, even among trained ob- 

 servers, agreed as to the direction whence the 

 sound came. This fact, and the simultaneity of 



