Resumé of Conclusions
1. There is no clear or uniform idea of what is meant by the direction of vibration as determined by non-instrumental observations; some persons regard it as the direction of transmission of a wave-like movement along the surface of the earth; others regard it as a to-and-fro movement like the gentle balancing of a rocking-chair.
2. The sensation at the time of an earthquake is commonly a confused tremulous one produced by jar rather than by wave-like motion having direction recognizable through personal sensations alone.
3. The overthrow of objects shows that the disturbance of equilibrium has very little regularity, and that it bears no definite relation to the direction of movement as indicated by instrumental obsrvation and by other evidences.
4. In many cases where the epicenter is known and the individuals over the area affected have stated their impressions of direction, these impressions are found to be quite useless for purposes of locating the epicenter or for any other purpose, so far as I can see at present.
5. Instrumental records show that the directions are many and the movements complex. Out of such entangled movements it seems quite impossible for our uncertain impressions to gather trustworthy conclusions regarding the location of epicenters.