September 10, 1886.] 



SCIENCE. 



243 



luindi-eds. The whole number of buildings dam- 

 aged was estimated between twelve hundred and 

 thirteen hundred, including twenty churches and 

 eleven chapels. The area of structural damage 

 was confined to fifty or sixty square miles in north- 

 east Essex, having its main axis in a dnection 

 north-east and south-west from Wivenhoe to Pei- 

 don. 



In considering the connection of the shock with 

 surface geology, the chief damage is found to have 

 been upon the London clay ; but some evidence 

 was found that the shock was spread widely, 

 especially toward the north and north-west, by 

 the better conducting older rocks which lie under- 

 neath. The excessive damage at Wivenhoe, as 

 well as its comparatively sudden decrease to the 

 north-east of that place, is attributed to reflection 

 of the earth- wave at that place by the valley of the 

 Cohie River. 



Attempts to estimate the velocity of projiaga- 

 tion, the exact location of the centrum, etc., are 

 admitted by the authors to be of little value as to 

 results, owing to the uncertainty of the data avail- 

 able in a country where earthquakes are rare, and 

 therefore find no one prepared for careful obser- 

 vation, and where also seismographs are practi- 

 cally unkno^vn ; but they furnish further evidence 

 of the care with which this report has been pre- 

 pared. 



Alphabetical catalogue of the earthquakes recorded as hav- 

 ing occurred in Europe and adjacent countries. By J. P. 

 O'Reilly. Dublin, 1886. 



The second memoir named aboved forms a part 

 of vol. xxviii. of the Transactions of the Royal 

 Irish academy. It is arranged on the same plan 

 as the similar catalogue of British earthquakes 

 published in 1884, by the same author, and which 

 forms an earlier part of the same volume of Trans- 

 actions. The present list is based mainly upon 

 those of Mallet, Perrey, and Fuchs, and aims to 

 give, for each of the localities arranged in alpha- 

 betical order, the number of recorded earthquake 

 shocks, with their dates and condensed indications 

 of the extent of the area affected. It forms a 

 volume of two hundred and twenty quarto pages. 



As it is very difficult, even where all the facts 

 are known, to make any numerical estimate of 

 intensity (and, moreover, for the vast majority of 

 recorded shocks no sufficient details are now avail- 

 able on which to base such estimate), tlie element 

 of intensity has been omitted in preparing this list, 

 and it represents only the number of recorded 

 earthquakes, the unit adopted being the shock. 

 When several or many or continuous shocks are 

 recorded, these are interpreted as meaning two or 

 tlu-ee or four shocks, — estimates which are cer- 

 tainly usually within the truth. It is also recog- 



nized that in the earlier centuries many earth- 

 quakes must have passed entnely um-ecorded, and 

 that the list is necessarily in so far an incomplete 

 record of the true number of earthquakes that have 

 occurred. 



In Professor O'ReLLly's former memoir concern- 

 ing British earthquakes, an earthquake map of the 

 islands was presented. The present list is not 

 accompanied by a corresponding map of Europe, 

 the prej)aration of which will necessarily involve 

 considerable time and trouble, and which, we hope 

 and expect, will in due time appear. In these 

 days when the graphical representation of all 

 physical phenomena has become so common, it is 

 certainly an important advance in seismology to 

 be able to apply the same methods to the study of 

 earthquake frequency in various parts of the world; 

 and we anticipate the day when a similar map of 

 the United States may be available for American 

 seismologists. Indeed, some progress has ah-eady 

 been made by the present wi'iter in the prepara- 

 tion of such a map. 



Statistik der erdbeben von 1865-85. Von 0. W. C. Fuchs. 

 Vienna, 1886. 



Dr. Fuchs's memoir is from the ninety-second 

 volume (1885) of the Sitzungsberichte of the Vienna 

 academy. In it he has collected the records of 

 earthquakes from his various annual reports, and 

 arranged them according to countries ; so that the 

 statistics for any i^articular locality for the whole 

 twenty years are now easily available to the stu- 

 dent. It forms another chapter in the general 

 earthquake catalogue which Mallet brought down 

 to 1843, and which Perrey continued for the later 

 years. It would be a desnable thing if Perrey's 

 lists for the years from 1843 to 1865, which are 

 scattered in numerous separate memoirs, could be 

 collected and collated in a similar way. In order 

 that the lists for different countries may be com- 

 f)arable one with another, Dr. Fuchs lias included 

 in his present lists only those shocks which were 

 sensible without instruments ; that is, those which 

 correspond to the numbers III to X in the Rossi- 

 Forel scale. The lists proper occupy about four 

 hundred octa\'0 pages, and are preceded by a brief 

 separate notice of the more important earthquakes. 

 It would have increased somewhat the usefulness 

 of Dr. Fuchs's book if he had added an index 

 of the countries ; but, as they are arranged geo- 

 graphically, the deficiency is not a serious one. 



Transactions of the Seismological society of Japan. Vol. 

 ix. part 1. Tokio, 1886. 



Vol. ix. of the Transactions of the Japanese society 

 opens with a jjaper occupying twenty-three pages, 

 by Dr. C. G. Knott, on earthquake frequency. 

 After a discussion of the probable length of any 



