H. P. Malet — On Earthquakes. 79 



that out of these strata, and these deposits, man obtains combustible 

 and inflammable materials, yet has he been unwilling to allow that 

 nature's laboratory is equal to his own. Some have rejected the 

 natural chemical theory of Sir Humphry Davy and others, that 

 volcanic action depends on local chemical causes. It has been boldly 

 and falsely asserted that the cause was not equal to the effect, and 

 that the chemical energies of our earth's materials were almost 

 wholly exhausted before the surface was consolidated. Nevertheless, 

 the hot spring flows, and the mountain labours. There may be local 

 exhaustion, but the energies of the earth are never lost, though they 

 may change from the inanimate to the animate, and back again. 

 Let those who suffer from these active energies talk of nature's 

 exhaustion if they please, but those who sit in their rooms, and 

 theorize on the subject, may as well hold their peace. Who will 

 venture to limit the quantity of any material, igneous or not, which 

 may have been collected into one region by the natural forces work- 

 ing at it for unknown millions of years ? The earth is full of 

 alkalis, as well as of gaseous materials. Spontaneous combustion 

 takes place in the little cargoes of our ships. Can we refuse a 

 simimr faculty to the great collections of the earth ? The material 

 is all the same ; nothing is hid in the strata of this earth that 

 was not once a partner in its surface produce, and nothing but 

 earth's produce takes fire in a ship's hold. We can neither limit the 

 collection of matter, or measure the energy of a collection. The 

 mountain in eruption discloses that, and the extinct volcanoes tell of 

 local exhaustion. If volcanoes were caused by the issue of heat from 

 the imaginary furnace of the earth, if the shrinking of the inner 

 crust produced mechanical causes of heat, and these were converted 

 into flames or steam by contact with water, there would be no cause 

 why an eruption, once commenced, should ever cease. We know 

 the force with which heat flies to a cooler atmosphere ; a channel, 

 once opened to that fire region, could never close again, eruptions 

 could never cease, and lava would flow while there was granite or 

 basalt to melt. Volcanic action is, however, spasmodic, and craters 

 do close up ; and so we at once come back to the earthquake cause of 

 the volcano. We have got our heating substances inside the earth, 

 we have got water percolating through the earth, we have vacant 

 areas beneath the surface. Along these water-courses, and into these 

 areas, the earth subsides or falls. There is no choice of locality for 

 these actions. The sandy plain, and the highest mountains in the 

 world, are alike liable to the law, and thus earthquakes are felt in 

 volcanic regions previous to eruptions. ^ It is only in these regions 

 that this effect takes place, and in these nature has deposited the 

 materials which produce heat. These materials are as liable to the 

 self-attraction of atoms, and to the eroding action of water, as any 

 other materials; they are therefore as liable to the laws of gravitation. 

 The grumblings and vibrations felt on the surface must be caused by 



^ These actions are confirmed by the Times, of 1st November, 1872: "Advices 

 from the Sandwich Islands report the volcanoes of M auna Loa Kilauea in a state of 

 active eruption, and it is stated that the shores of the island are sinking." 



