ON THE FACTS OF EARTHQUAKE PHENOMENA. 319 



tries under the Romish church it is often given in such vague form as " at 

 vespers," " after the morning mass," &c. 



The locality is the recorded place of occurrence, but it is obvious that in 

 most cases many other places were also more or less entitled to be recorded 

 as shaken; the place set down however has been, in the vast majority of in- 

 stances, either the most violently affected, or one of them; and, at least in the 

 absence of better information, must be viewed, unless otherwise stated, as 

 about the centre of disturbance. 



The direction, duration, and number of shocks, are seldom given ; the 

 scanty records of those most important elements best show how much we 

 must expect yet from future observations aided by instruments. Duration 

 also is often given in the middle ages in a strange and loose form, as in such 

 phrases as " during one Credo," or " while saying the Ave." 



In recording the phaenomena belonging to the sea and to the land deemed 

 worthy of notice, it may be remarked — 



Effects (secondary phaenomena) are only given, either as measures of the 

 violence of the shock, or as presenting some fact likely to be of importance 

 in earthquake dynamics. 



All phaenomena recorded as ha,\ing possible/ been due to earthquakes, of 

 which there are many, even in the catalogues of Von Hoff and Perrey, such 

 as landslips, abnormal tides, &c., are omitted, unless there exist some good 

 reason (such as an earthquake occurring at the same or nearly the time in some 

 other part of the world) to suppose a real connection with seismic causes. 

 And in selecting the phaenomena recorded, choice has been made of those of 

 most scientific importance, rather than those most curious to the mere general 

 reader. 



Wherever opportunity was had of consulting the original author or authors, 

 it has been endeavoured not to mention subsequently as an authority any 

 mere copyist from such original. It is to be regretted that in some other 

 catalogues this has not been attended to, and hence an event often appears 

 to be supported by a number of independent authorities, that, upon research, 

 all resolve themselves into copiers from one amongst them. Where there 

 are various accounts of the same event by different authors, attention has 

 been directed in choosing amongst them ; first of all, to the proximity of the 

 recorder both in time and in place, to the event, taking also into account the 

 general standard of authority or credibility of his works, as far as known 

 to us, and also the number of independent concurrent testimonies to the 

 event in more important cases. Where, as is often the case in older records, 

 the same historian is quoted indifferently under two or more names, one 

 name or title has been adhered to invariably. For example, Abulfaradsch 

 and Bar Hebraeus are two names for the same historian used indifferentlv by 

 Von Hoff. 



Some of the very early authors, such as Julius Obsequens, and many of 

 those about the decline of the eastern empire, appear, at least as regards our 

 subject, of very doubtful authority, and it is scarcely necessary to say that 

 the same remark may apply to many records of Chinese and Japanese earth- 

 quakes. The records multiply in number and increase in accuracy and au- 

 thority as we pass down the stream of time ; and within the last 200 years is 

 embraced a mass of earthquake incident, probably from these causes, equal 

 in scientific value to the whole of the preceding parts of the catalogue. 



The influence of commerce and navigation in modern times upon obser- 

 vational science, and of the disenthralment of mankind, in Europe at least, 

 from much of the superstition and tyranny of the middle ages, could scarceljr 



