337 



that the notion of the existence of a luminiferous ether, capable 

 by its vibrations (and perhaps in other ways) of affecting the 

 relations of ponderable matter has become essential to the 

 thoughts of the modern chemist. 



40. The Professor says : " Euler established the principle 

 that a substance absorbs all those rays of light with whose rate 

 of vibrations the vibrations of its smallest particle can agree. 



" Each molecule of a substance, according to its chemical 

 structure, has certain determinate rates of vibration. If it is 

 struck by a wave [of ether] whose period agrees with one of 

 those proper to itself, it is set in motion, or has its motion 

 strengthened if it has already been vibrating. The wave gives 

 up its energy, wholly or partly, to the molecule, goes through 

 the substance weakened, or does not go through it at all, i.e., it 

 is absorbed.'' 



41. We have arrived at the conclusion (in accordance with 

 the above principle) that the chlorophyll, or green of the leaves, 

 derives all its power of fixing carbon, that is of growth and 

 increase, from the action of the rays of light upon it. This, 

 indeed, has been abundantly proved in other ways. Thus it 

 has been shown, that if a tuber of potato is allowed to vegetate 

 in the dark, although it puts forth leaves and shoots, and does 

 its utmost (so to speak) to form a plant, yet being deficient in 

 the effects of light, and consequently not assimilating carbon, 

 it forms all this pseudo-growth at the expense of the substance 

 stored up in the tuber, and in the end weighs no more than it 

 did at the beginning. 



42. Thus, without the luminiferous ether there could be no 

 light, without the vibration of its waves no vegetation, and without 

 vegetation the world would be a waste, devoid of vegetable and 

 consequently of animal life. 



43. All our existence here rests, then, upon a scientific fact, 

 which the disciples of M. Comte are Ijound to reject as inca- 

 pable of proof, and excluded from belief by the golden maxim, 



the first commandment of science.'^ 



Part IY. — The Spiritual World. 



44. Professor Huxley enunciates that there is a path that leads 

 to truth so certainly that any one who will follow it must needs 

 reach the goal, whether his capacity be great or small. And 

 that there is one guiding rule by which a man may always find 



