452 THE MULTIPLICATION OF EFFECTS. 



of igneous matter, the propagation of earthquake vibrations 

 thousands of miles around, the loud explosions, and the es- 

 cape of gases, there would be the rush of the Atlantic and 

 Pacific Oceans to supply the vacant space, the subsequent 

 recoil of enormous waves, which would traverse both these 

 oceans and produce myriads of changes along their shores, 

 the corresponding atmospheric waves complicated by the 

 currents surrounding each volcanic vent, and the electrical 

 discharges with which such disturbances are accompanied. 

 But these temporary effects would be insignificant com- 

 pared with the permanent ones. The complex currents of 

 the Atlantic and Pacific would be altered in directions and 

 amounts. The distribution of heat achieved by these cur- 

 rents would be different from what it is. The arrangement 

 of the isothermal lines, not only on the neighbouring con- 

 tinents, but even throughout Europe, woujd be changed. 

 The tides would flow differently from what they do now. 

 There would be more or less modification of the winds in 

 their periods, strengths, directions, qualities. Rain would 

 fall scarcely anywhere at the same times and in the same 

 quantities as at present. In short, the meteorological condi- 

 tions thousands of miles off, on all sides, would be more or 

 less revolutionized. In these many changes, each of which 

 comprehends countless minor ones, the reader will see the 

 immense heterogeneity of the results wrought out by one 

 force, when that force expends itself on a previously compli- 

 cated area ; and he will readily draw the corollary that from 

 the beginning the complication has advanced at an increas- 

 ing rate. 



159. We have next to trace throughout organic evolu- 

 tion, this same all-pervading principle. And here, where 

 the transformation of the homogeneous into the heterogene- 

 ous was first observed, the production of many changes by 

 one cause is least easy to demonstrate. The development of 

 a seed into a plant, or an ovum into an animal, is so gradual; 



