15 
form, and go on rotating, it was evident the planets rotated in the 
same direction, and nearly in the same plane, asthe sun. Not 
only did geology show that the earth had passed through various 
stages of development, but spectrum analysis revealed the fact 
that the composition of the sun and earth was the same, and 
meteorites contained the same metals as our earth. 
The rocks forming our earth’s crust were both aqueous and vol- 
canic, and though the latter agency was now less violent than in the 
past, still very great submarine action was going on and raising the 
bed of the Pacific Ocean. Countries like France, India, &., in which 
no volcanoes at present are in an active state, had, ages ago, as 
evidenced by the nature of their mountains, been centres of great 
disturbance. 
Turning to the 400 active volcanoes, they could be ar- 
ranged into 22 series, and were most of them near the sea and 
nearly parallel to the coast line; their heights, which varied from 
939ft. to 23,000ft. above the level of the sea, their geographical 
position and dates of eruption had all been tabulated; yet no 
systematic observations had been made on any oneof them. It had 
been noticed that earthquakes preceded or followed volcanic erup- 
tions, as was the case with the earthquake at Lisbon, which shook 
one-twelfth part of the earth’s surface; and the eruptions of Vesuvius 
in 1767, so well described by Sir W. Hamilton. The interior of 
the earth contained a molten mass, portions of which, separating, 
caused local action ; when the molten matter came in contact with 
water, it swelled out and produced upheavals, fractures, &c. 
Looking at the volcanoes it would be seen they were in parallel 
lines, having a spiral tendency, and corresponding to the cork- 
screw motion of the earth. The great mass of volcanic action lay 
between the tropics ; if beyond, it was deeply connected with the 
molten matter. From the comparative density of the earth, 
it was evident the mass augmented in density towards the centre, 
in addition to the tendency of pressure to produce a similar result. 
Not only on the earth, but in the moon, evidences of volcanic 
action were apparent, and almost nightly Pratt, of Brighton, was 
adding something new in connection with the Volcano Plato. 
Solar spots and other phenomena shewed that great volcanic dis- 
turbances were going on in the sun, while spectrum analysis 
revealed the fact that it was in a state of perpetual incandescence. 
