70 Ihe Causes and Phenomena of Earthquakes. 



in 1834. I will point to some of the diagrams exhibiting his 

 views. 



His opinion on elevation is, that eruption of the feu igne cen- 

 trale, the sinking of the crust at the top of its elasticity, and the 

 eboulement of strata into great depths, produced by the pressure 

 of water, and the upward interior pressure of the outward crust 

 in the direction of certain radii, generate upheaval, contortion, 

 and tilting of strata. 



He explains ocean currents by volcanic action, as correspon- 

 ding with magnetic aerial motion, and also says, he has dis- 

 covered a volcanic channel flowing round the globe between two 

 parallels ; and that volcanos are like knots on a string, which 

 must partake any shock communicated to either extremity. 



Reasoning in this way, he has some speculations on the fact 

 (as he asserts it) that Gillolo, one of the Celebes Islands, the 

 Sandwich Islands, and the Isle de Bourbon, in the Indian Ocean, 

 are seismosically connected. 



If this be true, the late eruption in the Sandwich Islanas 

 ought to have some corresponding effects elsewhere, especially in 

 Gillolo, for the accounts of which we must patiently wait. In 

 1813 a most fearful eruption took place (as in 1673) in Bourbon ; 

 the Moluccas did not reply to it ; GKllolo alone was shaken ; but 

 the Sandwich Islands immediately erupted. 



And it appears that when the latter are affected so is the 

 former, as is stated in the Transactions of the Royal Society of 

 London. In the eruption of 1682 and 1683 Bourbon was 

 affected, and 1691 the Sandwich Islands and Bourbon were 

 affected at the same time. Gillolo is considered by De Bylandt 

 as intermediate between the two hemispheres, 



I refer to this example to illustrate the views of the author in 

 question, who thus shows, according to his theory, that though 

 the Moluccas are the great source of terrestrial derangement in 

 the Eastern hemisphere ; yet Gillolo being sometimes affected 

 independently of the rest, is connected not only w T ith Bourbon 

 and the Sandwich Islands, but with the central source of volcanic 

 action. The West Indies represent the great Western source, 

 corresponding in position with the Moluccas. 



Turning now from this brief reference to M. de Bylandt, as 

 belonging to volcanos, I may quite as briefly state his views on 

 earthquakes. 



He presumes, that when vibration or oscillation, produced by 

 earthquake shock, takes place, the effect perceived is contra- 

 dictory to supposed experience. Thus, a vibration felt from 

 north to south really comes from the latter direction. He con- 

 siders vertical as direct, and horizontal as indirect shocks, to come 

 from the central fire, and that circular or accidental shocks 

 belong to no particular cause. He attributes the first chiefly to 



