ANTAGONISM. 611 



then tlie luminosity gradually faded, the star became more and 

 more dim, and ultimately disappeared. The spectrum of it 

 showed that the light was compound, and had probably emanated 

 from two different sources. It was probably of a very high tem- 

 perature. If this theory of temporary stars be admitted, we get 

 a nebula of vapor or star-dust again, and so may get fresh in- 

 stances of the nebular hypothesis. 



Let us now take the earth itself. It varies in temperature, and 

 consequently the particles at or near its surface are in continuous 

 movement, rubbing against each other, being oxidized or deoxi- 

 dized, either immediately or through the medium of vegetation. 

 This also is continuously tearing up its surface and changing its 

 character. Evaporation and condensation, producing rain, hail, 

 and storms, notably change it. Force and resistance are con- 

 stantly at play. The sea erodes rocks and rubs them into sand. 

 The sea quits them and leaves traces of its former presence by the 

 fossil marine shells found now at high altitudes. Rocks crumble 

 down and break other rocks, or are broken by them ; avalanches 

 are not uncommon. The interior of the earth seems to be in a 

 perpetual state of commotion, though only recurrent to our obser- 

 vation. Earthquakes in various places from time to time, and, 

 doubtless, many beneath the sea of which we are not cognizant, 

 nor of other gradual upheavals and depressions. Throughout it 

 nothing that we know of is at rest, and nothing can move without 

 changing the position of something else, and this is antagonism. 

 Metals rust at its surface, and probably they or their oxides, chlo- 

 rides, etc., are in a continuous state of change in the interior. 

 Nothing that we know of is stationary. The earth as a whole 

 seems so at first sight, but its surface is moving at the rate of 

 some seventeen miles a minute at the equator ; and standing at 

 either of the poles — an experiment which no one has yet had an 

 opportunity of trying — a man would be turned round his own 

 axis once in every twenty-four hours, while the earth's motion 

 round the sun carries us through space more than a million and a 

 half of miles a day. The above changes produce motion in other 

 things. The earth pulls the sun and planets, and in different de- 

 grees at different portions of its orbit. 



Before I pass from inorganic to organized matter, I had better 

 deal with what may perhaps strike you as the most difficult part 

 of my subject, viz., light. Where, you may say, is there antago- 

 nism in the case of light ? Light exercises its force upon such 

 minute portions of matter that until the period of the discovery 

 of photography its physical and chemical effects were almost un- 

 known. Such effects as bleaching, uniting some gases, and affect- 

 ing the coloring-matter of vegetables, were partly known but little 

 attended to ; but photography created a new era : I shall advert 



