ON THE EAETHQUAKE AND VOLCANIC PEENOMENA OF JAPAN. 303 



holes have been formed at the time of almost every large earthquake ; 

 while, so far as I am aware, they have never been formed by the falling of 

 rocks at the time of a volcanic eruption. Professor Sekiya is now engaged 

 upon a monograph describing in detail the eruption. 



The Vibrations of Locomotives, Roleing-Stock, and Structures. 



At the suggestion of Mr. John MacDonald, superintendent of the locomo- 

 tive department at Shinbashi, in Tokio, I was led to make experiments on 

 the vibrations of locomotives. Owing to the violence of the motion and 

 the actual tipping which is experienced on an engine, I found that ordinary 

 earthquake machines were valueless, and in oi-der to obtain an instrument 

 suitable to record the particular class of movements, it would be necessary 

 to make experiments. Through the kindness of Mr. Frank Trevithick, 

 C.E., the general superintendent of the Shinbashi works, I was able to test 

 a considerable number of contrivances, and I think I may fairly state 

 that I have obtained an instrument which practically gives an absolute 

 measure of the horizontal and vertical vibrational movements of loco- 

 motives. These vibrations are recorded as three components — one 

 vertical, one longitudinal, and one transverse. Each of these components 

 is recorded by a brass pointer writing on metallic paper covering a re- 

 volving drum. The diagrams are therefore continuous, and give a record 

 of all the vibrations of an engine while on a given journey ; and araono-st 

 other things they show the following : 



1. Variations in the speed of a train, as, for instance, in ascending 



and descending inclines, or when approaching or leavino- a 

 station. 



2. They show all the places where a train may have stopped, and the 



duration of the stoppage. 



3. The relative extent of motions in different directions. For 



example, in an engine with its wheels balanced in a particular 

 manner the longitudinal vibrations are very much greater than 

 the transverse motions. It would seem as if the eno-ine was 

 exerting its power by a series of jerks. In another engine the 

 transverse oscillations are the greater, and these, if too large, 

 might be dangerous to the safety of the train. In fact the 

 diagrams test the nature of the balancing of the engine. 



4. From the diagrams much may be learnt about the nature of a 



track. The curves on the line are clearly marked, soft ground 

 is indicated, and irregularities due to faultiness in the tmck are 

 recorded. 



In short, the instrument gives an automatic log of the run of a loco- 

 motive, it tests its balancing, and it records irregularities or imperfections 

 on the line. 



Although this instrument is not directly connected with seismological 

 work, it is a useful outcome of such work, and it has given valuable sugges- 

 tions as to the construction of seismographs for large earthquakes, in 

 which there are undoubtedly quick and sudden changes in level. 



BuiEDiNG IN Earthquake Countries. 

 Last year, at the suggestion of his Excellency Arinori Mori, the late 

 Minister of Education, a committee, consisting of engineers, architects, 

 and other specialists, was called together to discuss the forma of constrnc. 



