100 



EARTHQUAKES, 



the arches had been put in. As these foundations were 

 unusually strong, being intended to carry so very much 

 greater weight than that to which they had been subjected, 

 if any settlement had been detected it would have been a 

 matter of surprise. 



Some weeks after the formation of these cracks it was 

 observed that they gradually closed. This was probably 

 due to the gradual falling inwards of the two broken por- 

 tions of the arch, their position when open being one of 

 instability. 



Had this building been more complete at the time of 

 the shock, and the heavy walls been tied together at 

 higher points, although the archways would have been 

 points of weakness, it is quite possible that fracture would 

 not have taken place. This illustration shows us that when 

 a building is shaken in a definite direction there will be 

 some rule as to the positions in 

 which fractures occur. As an- 

 other example, we may take the 

 observations of Alexander Bittner 

 upon the buildings of Belluno 

 after the shock of June 29, 1873 

 (see Beitrage zur Kenntniss des 

 Erdbebens von Belluno am 29 

 Juni, 1873, p. 40. Von Alexander 

 Bittner. Aus dem LXIX. Bande 

 der Sitzungsb. der K. Akad. der 

 '~ ^- ^::^-rir^ Wissensch., II. Abth., April- 

 FlG. ] 6.— Cracks in a corner Heft. Jahrg. 1874). 



mfcBw' """ '"• Speaking generally, he re- 



marks that 'Houses similarly 



situated have suffered in corresponding walls and corners 



in a similar manner. In Belluno there is a certain kind 



of damage which is repeated everywhere, making a pecu- 



