— 
ON THE EARTHQUAKE PHENOMENA OF JAPAN. Sin 
The analysis of the diagrams from which the above tables have been 
calculated has not yet been completed. Some of the more important 
results to which they point are as follows :— 
1. All stations have invariably given different records for the same 
earthquake. The principal differences relate to direction, period, ampli- 
tude, maximum velocity, and maximum acceleration. 
2. On the hard ground, as at C and D, the amount of motion is very 
much less than at the remaining stations, like A, B, F,and E. Com- 
paring together the average maximum velocities and maximum accelera- 
tions at C and E, we see that they have respectively been as 1 to 5 and 
1 to 2:4. A practical conclusion to be drawn from this is that a house 
at C might stand whilst a similar house at E might be shattered. 
3. Similar waves only appear in the diagrams at different stations 
where an earthquake is strong. 
4. As a disturbance passes from station to station the time interval 
between two similar waves suffers a change. This leads to uncertainty 
in determining the velocity with which a disturbance travels. 
Other results to be derived from these observations will be given at 
a future period. In the tables of the report upon stations A, B, and C, 
published in 1884, several misprints occurred. These are now cor- 
rected, 
Experiments on a Building to resist Earthquake Motion, 
In the report of last year I described a house which rested at its 
foundations upon cast-iron balls. These balls were 10-inch shells. The 
records obtained from an instrument placed inside this house showed 
that, although it was subjected to considerable movement at the time of 
an earthquake, all sudden motion had been destroyed. Although the 
balls did very much to mitigate earthquake motion, wind and other 
causes produced movements of a far more serious nature than the earth- 
quake. ‘To give greater steadiness to the house, 8-inch balls were tried, 
and then 1-inch balls, Finally the house was rested at each of its piers 
upon a handful of cast-iron shot, each {inch in diameter. By this 
means the building has been rendered astatic, and, in consequence of the 
' great increase in rolling friction, sufficiently stable to resist all effects 
like those of wind. The shot rest between flat iron plates. That the 
house had peculiar foundations would not be noticed unless specially 
pointed out. The motion experienced in the house is indicated in 
column G of the preceding tables. The best idea of this motion is seen 
by reference to the accompanying diagram, taken on February 12, 1885. 
From this diagram it will be seen that in the house only two small 
shocks, A and B, were recorded, whilst at all the other stations, not only 
were there many shocks equivalent to A and B, but there were many 
which were greater. From these experiments it seems evident that it is 
possible to build light one-storied structures of wood or iron in which, 
relatively to other houses, but little movement will be felt. 
Observations in a Pit 10 feet deep. 
The instrument placed in this pit is similar to all the other instru- 
ments, and is installed in a similar position. Column H in the preceding 
tables refers to the observations which have been made. Comparing the 
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