Revieivs — Professor W. H, Hohhs on Earthquakes. 133 



in conjunction, and side by side, of pendulums of very different lengths, 

 and by the use of various systems of damping, this disadvantage 

 may be diminished, though it can never be quite overcome. Hence 

 the seismological observatory which has installed in it the most 

 numerous and most varied types of instrument may be expected to 

 obtaia the best and most complete records. Eut there is another 

 and very practical consideration that must also be kept in view. 

 Not only is it desirable that the most delicate observations should 

 be made at a particular spot, but it is equally important that records 

 shouhl be obtained at numerous and widely distributed stations, by 

 means, if possible, of instruments of the same pattern, the records of 

 which can be directly compared. In the selection of an instrument 

 suitable for this work, it becomes absolutely imperative that the 

 original price should not be so great as to make it prohibitive, and 

 that the cost of maintenance (including photographic materials, etc.) 

 should not be excessive. It is these considerations which have 

 necessarily governed the action of the Seismological Committee of 

 the British Association in the work they have carried on for so many 

 years, and by their observance the Secretary of the Committee, 

 Professor John Milne, has been able to establish and to keep 

 maintained some forty seismological stations scattered all over the 

 globe. The only reference to the Milne instrument in this work is 

 a remark on the small amount of magnification of the movement 

 of the earth particle in that instrument, and the author does not 

 appear to be aware that this defect has already been removed by an 

 addition to the instrument made by Professor Milne himself. 



The Seismological Committee of the British Association can point 

 with confidence to the important results obtained through the use 

 of this instrument of Professor Milne's during the last twelve years. 

 It has been asserted that an instrument of the Milne type, established 

 at Strasburg, has not given satisfactory results. But how far this 

 may have been due to want of proper adjustment or other causes is 

 somewhat doubtful. The important point to be remembered is that 

 a very large part of our knowledge concerning the distant effects of 

 earthquakes, since the original work of Von Kebeur-Paschwitz, has 

 been obtained by a comparison of the records obtained with the 

 Milne instrument at widely distant stations. The author of this 

 work, in his references to the labours of Professor Milne, is so fair and 

 appreciative that we feel sure any seeming neglect of results obtained 

 during eighteen years in Japan and twelve years subsequently at 

 Shide must be due to misinformation and certainly not to personal 

 prejudice or ill-will. We can very heartily recommend the work as 

 giving a full and very clear account of the recent developments of 

 what the author not inappropriately calls the New Seismology, 

 dealing with the observations of earthquakes at a distance, and the 

 conclusions to be drawn from such observations. 



J. W. J. 



