Febeuaey 18; 1898.] 



SCIENCE. 



233 



cut in two points, is the only one which as 

 a whole is freely movable in itself. 



Then Klein says : "I consider all the 

 topologically distinguished space-forms as 

 equally compatible with experience. That 

 in our theoretic considerations we prefer 

 some of these space-forms (namely, the 

 family types, that is, the properly parabolic, 

 hyperbolic, elliptic) in order to finally as- 

 sume the parabolic geometry, that is, the 

 customary Euclidean geometry, as valid, 

 happens simply from the principle of 

 economy." 



Geoege Bruce Halsted. 



Austin, Texas. 



EARTHQUAKE SHOCKS IN GILES CO., VA* 

 Immediately following the earthquake of 

 May 31, 1897, which was distinctly felt over 

 most of the eastern portion of the United 

 States, came newspaper reports of continued 

 disturbance in the form of explosions and 

 earth tremors in Giles county, Virginia. It 

 was also reported that Mountain Lake had 

 been drained, that the wells of Saltville, 

 Virginia, had ceased to flow, and that large 

 fissures had opened in the earth at various 

 points in Giles county. At the urgent re- 

 quest of several citizens of Pearisburg, and 

 with the idea that possibly there might be 

 some foundation for the rumors afloat, I 

 visited the region in the early part of June. 

 The reports were found to be grossly ex- 

 aggerated, as no disturbance had occurred 

 at Mountain Lake, the Saltville wells were 

 flowing as usual, and no fissures had ap- 

 peared within the limits of Giles county. 

 Under the circumstances the scientific re- 

 sults of my visit were insignificant, but 

 there were certain phenomena observed 

 which seemed to be worth recording. 



The county of Giles lies on the north- 

 western side of the Appalachian Valley. 

 Its surface is diversified by numerous ridges 



* Published by permission of the Director of the 

 United States Geological Survey. 



which cross the country from northeast to 

 southwest. The rocks have been thrown 

 into great folds, and are broken by nu- 

 merous faults which also cross the re- 

 gion in the same direction. The principal 

 object of my visit was to determine, if pos- 

 sible, whether there was any relation be- 

 tween the present disturbance and the 

 geologic structure of the region ; but, from 

 the nature of the case, only a little informa- 

 tion was obtained on the subject. 



The earliest generally recognized earth 

 tremor occurred on May 3. It loosened 

 some bricks from old chimneys and was ac- 

 companied by considerable noise, like low 

 rumbling thunder. From May 3 to 31 no 

 shock of importance occurred, but many 

 noises were heard, similar to the rumbling 

 that accompanied the first quake. Many 

 persons now believe that the same sort of 

 noises occurred for a long time prior to 

 May 3, but were passed unnoticed by the 

 people, who, at that time, did not have 

 their nerves wrought to such a tension that 

 they heard and felt the slightest shock or 

 earth tremor. 



The shock of May 31 was probably more 

 severe in and about Pearisburg than at any 

 other point from which I have information. 

 No serious damage was done even here, but 

 old brick houses were badly shaken, and 

 many chimneys were cracked and the top- 

 most bricks hurled to the ground. Much 

 noise accompanied this shock, and many of 

 the inhabitants, already much disturbed by 

 the previous heavy shock and the continued 

 rumblings beneath them during the month, 

 were terror-stricken. The noise did not 

 stop with the main shock, but tremors and 

 rumblings, or sharp reports, are described 

 as occurring during the entire night follow- 

 ing the shock. The intensity of these 

 rumblings or reports varied according to 

 location. Those of greatest severity were 

 reported from the angle between Sugar Eun 

 and Pearis Mountains. Old veterans of the 



