~“I 
ON SEISMOLOGICAL INVESTIGATION, 21 
Earthquakes recorded at Shide and at Distant Stations, 
The preceding table shows the earthquakes which were recorded in the 
{sle of Wight and also at distant stations. When comparing the records 
at one station with those taken at any other station, consideration must 
be given to the dates on which these stations commenced their observa- 
tions. For example, the Kew entries corresponding to those at Shide lie 
between Nos. 195 and 271 or April 25, 1898, and March 25, 1899. Just 
as comparisons may be made between the Isle of Wight list and that from 
Kew, showing that many earthquakes were recorded at the former place 
which were not recorded at the latter, exactly opposite comparisons might 
be made. For example, whilst the above list indicates that Kew only 
recorded forty-two disturbances out of fifty-seven noted at Shide, the 
complete register for Kew (p. 166) indicates that at that place seventy-five 
disturbances were noted, and it is possible that more than forty-two of 
these were common to other countries. 
Although the Indian stations have recorded earthquakes which have 
also been observed in other parts of the world, in consequence of difti- 
culties largely the result: of a tropical environment the value of many 
seismograms has been impaired. Until these difficulties have been over- 
come the frequency of earthquakes common to India and other parts of 
the world can only be imperfectly indicated. 
Although the instruments at Bidston and Edinburgh have yielded 
excellent results respecting slow changes in the vertical, and as such are 
important adjuncts to a seismological laboratory, yet the above table 
indicates that they fail to pick up many earthquakes. 
Analysis of the Table from a Seismometrical Point of View. 
The last line of the table shows that Kew, Toronto, Victoria, 
Bombay (?), Nicolaiew, Potsdam, and Trieste have recorded more earth. 
quakes in common with the Isle of Wight than have been recorded at the 
Ttalian stations. This conclusion is more clearly indicated in the follow- 
ing table :— 
Out of 57 records at Shide 42, or 73 per cent., are common to Kew 
61 Ld hol of ra Toronto 
” ” ” ~ 
je moe + PP 18 ,, 56 - 35 Victoria, B.C. 
” 42 ” ” 9 ” 21 ” 99 Batavia 
ey aD) 35 rs 25 ,, 58 > 5 Nicolaiew 
Py oy tees as - 29 ,, 60 Fe a Potsdam 
a re i A 13 ,, 65 Ho 5 Trieste 
” 66 ” ” 25 ” 38 ” ” Italy 
If the Italian stations are taken separately the percentage for each is 
lower than that for Italy as a whole. When we compare the twenty-four 
earthquakes recorded at Shide, Nicolaiew, and Potsdam which lie between 
Nos. 182 and 250 with those noted in Italy, we see that six of these, viz. 
Nos. 182, 185, 210, 231, 248, and 264, apparently escaped observation in 
the latter country. 
Again, out of thirteen disturbances noted in Trieste and in the Isle 
of Wight, only six of these, viz. Nos. 255, 257, 259, 260, 264, and 266, are 
found in the Italian register. It will also be observed that some of the 
shocks which escaped the Italian instruments were well recorded in Toronto, 
Victoria, B.C., Batavia, and other places; and it may be added that 
if we except Nos. 182, 260, and 266, the seismograms representing these 
shocks from Shide, Potsdam, and other places are of marked magnitude. 
