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2. The vibrations from some distant centre, or centres, of 
voleanie activity. 
3. Minor forces, comparatively local, excited into sympathetic 
activity, by some distant or general disturbance. 
The first of these, I think, we may dismiss. As I remarked 
in discussing the 183th July tremor, ‘immediately over the 
focus of the disturbance the motion would be vertical, the 
earth-wave becoming more and more inclined as it recedes 
from that point. 
Now, my seismometer readings indicate great inclination, or 
very minute vertical motion in comparison with the horizontal. 
This has been the general indication of my seismometers. 
The second hypothesis is rather favoured by the records of 
the great shocks 13th July, and 19th September ; but, against 
that, we have no knowledge of any sudden or violent con- 
vulsion in the direction indicated. Still, that there are forces 
at work in that direction is evidenced by the boiling springs, 
as well as at least one active voleano in New Zealand. It is, 
I think, not improbable that deep subterranean action of no 
ereat violence might propagate its vibrations to a long 
distance. 
The third hypothesis fits in with the fact, which should not 
be overlooked, that during the whole period of these tremors, 
the entire globe has been ina state of abnormal disquiet. 
Within the period, there have been terrible earthquakes at 
Ischia and Sunda, besides lesser in Persia, Asia Minor, 
Spain, England and other places; also numerous volcanoes 
abnormally active, and new ones breaking out in all directions 
from Iceland and Alaska northwards, to New Zealand at 
least southwards. (Those at the extreme south we do not 
know about.) If the origin of our tremors were some fixed 
centre, I think we should not have had so much trouble in 
determining its position. After making all allowance for 
errors in time, I think the indications go to show that the 
minor tremors at least proceed from various directions. This 
again favours the third hypothesis. 
If we might admit the probability of our being affected 
by shocks from the antipodes, it would almost seem as if our 
tremors had some indirect connection with earthquakes that 
have occurred the other side of the world. For comparison, 
I give below the dates of earthquakes in other places, with 
the nearest period of special activity in Tasmania :— 
On 28th July, 1883, occurred the earthquake of Naples, 
and on 80th we had several tremors during the day, some of 
them felt generally throughout the island. 
On the 26th August was the outbreak at Sunda. 
We had an increase on 28th, culminating on 30th. 
