2ZJ4 JOURNAL OF SCIENCE. 



By the courtesy of Dr. Lemon, Superintendent of Posts and 

 Telegraphs, a system Las been in working for nearly two years in 

 New Zealand, by which the telegraph officers at any stations at 

 which an earthquake is felt forward memoranda of the fact to Dr. 

 Lemon, who sends them on to me. These memoranda are made on 

 forms supplied to them. (See below.) A few private persons have 

 kindly given me assistance by filling up and forwarding memoranda, 

 and I shall be happy to send blank forms to any willing to help by 

 recording the earthquakes that come within their own observation. 



Last year I received in this way 79 memoranda with notes of 47 

 shocks, and was able to determine with tolerable exactness the origin 

 of one earthquake, and approximately' those of several others. This 

 year I have received 75 so far, but the results are not yet worked out. 

 I quote these facts to show that something may be done without the 

 aid of instruments; but, even if the instruments Avere obtained and 

 set up at chosen places, it would be desirable to continue the present 

 system for the purpose of checking and corroborating the conclusions 

 arrived at by their means. 



I shall conclude by a few brief remarks on one or two of the 

 headings of the form supplied to the officers of the telegraph 

 department. 



1. Time of beglnnimj of shock. If possible, N.Z. Mean Time. 

 What we really want to get is the time at each place of the same 

 phase of the earthquake, and it is generally agreed that the best time 

 to observe is the beginning of the first maximum. Now that is 

 generally the moment at which most people begin to notice the 

 motion, and therefore anyone answering the question precisely would 

 in all probability give what is wanted. It is important that the time 

 should be checked by communication with Wellington as soon after 

 the shock as convenient ; . if any considerable time has elapsed the rate 

 of the watch or clock by which the time was observed should be 

 found, and allowed for. 



4. Apparent Direction. People are very often deceived, some- 

 times unavoidably, as to the direction from which a shock proceeds. 

 The best indicator generally available would be any object hanging 

 freely and swinging to and fro {eg. a chandelier or lamp). The 

 direction of the swing may be seen by fixing the eye upon some point 

 on the ceiling or wall. Other means of noting direction of shock are 

 by the overflow of milk or other liquids in open vessels, by the 

 rattling of pictures against or along the wall, or by the falling of 

 crockery, etc., from shelves. By far the best of all these ways is that 

 given by the swinging of suspended objects, and the beginning of the 

 swinging should be noted, if possible. The direction taken by falling 

 objects depends very much, on the nature of the previous support. 

 Two directions, — one belonging to the normal, the other to the 

 transverse vibrations, commonly but not always at right angles, are 

 often observed, — both should be noted. 



The other particulars asked for serve to check and confirm the 

 conclusions formed from the notes of lime and direction, and may now 



