147 
came flattened. At thirty-five minutes past 7 o’clock two other 
islands appeared to the southward of the first. Of these, the most 
southern bore south 56° west. The three islands appeared to run 
in the direction of north and south. The sea broke with violence 
upon their shores and seemed violently agitated. In the distances 
between these islands nothing was visible but chains of rocks, among 
which a great explosion was discernible. 
*«« At eight minutes before 8 o'clock, the most northern island was 
the only one visible: it appeared much higher than before, and of 
the shape of a sugar loaf. ‘The darkness of the night prevented us 
seeing the other two islands. 
«The following day, the 13th of the month, at a quarter past 1 
o'clock in the morning, the larboard watch and myself saw at inter- 
vals a light in the same direction as the islands, south 72° west, 
which appeared to be caused by a volcano. 
Position of the most northern island: 
Long. W. of meridian of Cadiz, 70° 33! (76°52! W. of Greenwich.) 
Wixi Noah (eee Wadetsee Shae Sonoda), Ors. 
Position of the most southern island: 
Long. W. of meridian of Cadiz, 70° 34! (76° 53’ W. of Greenwich.) 
ears eee ssh sadleaies noogaoanbencoce 33 40. 
*« I consider my longitude to be correct from having sighted Juan 
Fernandez on the 11th, at 8 o’clock in the morning, and compared 
its bearings with my latitude by observation. 
«Signed, &c. &c. &c.” 
Mr. Caldcleugh adds, the master of another vessel reported that 
the isiands bore 30 leagues due east of Juan Fernandez; and that a 
ship had been despatched from Valparaiso to discover whether they 
remained above water or had crumbled away. 
The larger Curauma Point, referred to in the declaration, is a bluff 
point, about 400 feet in height, and situated to the southward of 
Valparaiso. 
A letter was next read, addressed to Charles Lyell, Esq., V.P.G.S., 
by John Buddle, Esq., F.G.S., on depressions produced in the sur- 
face of the ground by excavating beds of coal. 
Subsidence of the surface invariably follows the working of the 
subjacent beds of coal where sufficient supports are not left, but the 
extent of the subsidence is governed by the following circumstances : 
lst. The depth of the seam of coal below the surface. 
2nd. The thickness of the seam or seams removed. 
érd. The nature of the strata between the surface and the seams 
of coal. 
4th. Whether the pillars of coal are wholly or partially worked. 
If the depth from the surface does not exceed 30 fathoms, and sand- 
stones form the predominant strata, the subsidence is about equal to 
the thickness of the seam of coal removed; but if metal-stone con- 
stitute the greater portion of the intervening mass, the amount of de- 
pression in the surface is less. This rule is considered to hold good 
at all depths. 
nw 2 
