2o8 SPECULATIVE SCIENCE 



attracts Sirius across space, and yet the space between is as if 

 neither Earth nor Sirius existed ! Can these things be ? We 

 think not ; and Newton himself did not affirm this ; his work 

 was to prove a fact, and he neither affirmed nor denied the pos- 

 sibility of a medium of communication. That was a secondary 

 question then, but now that the fact of the attraction is esta- 

 blished the secondary question has risen to the first rank, and we 

 must consider whether the intermediate space really contains 

 nothing which plays a part in gravitation. 



Analogy is against such a supposition. The influence ex- 

 erted at a distance by electricity, magnetism, heat, and light, is 

 effected by the substances filling intermediate space. For every 

 one of these influences we suppose some intermediate material, 

 and the existence of this material, often called an ether, is 

 almost demonstrated. Faraday, by proving the influence of the 

 intermediate material in the case of electrical action, by his 

 discovery of magneto-optic rotation, and by showing how lines 

 of force arose in media, rudely shook the theory of attraction 

 and repulsion, exerted at a distance across a perfect void. Light 

 gives us a very perfect analogy to illustrate our assertion that 

 the law of gravitation is not an hypothesis, but a result capable 

 of and requiring further explanation. Gravitation is not per- 

 ceived directly by the senses, except in the case of the attraction 

 of the earth. We have a special sense for the perception of 

 light, yet many phenomena of radiation are not detected by the 

 eye. Similarly, some of the phenomena of gravitation may 

 escape our observation. Newton detected some of these. Sup- 

 pose we had all been blind, Newton, instead of discovering 

 universal gravitation, might have discovered light and its laws. 

 From observations on the growth of vegetation, the sensation of 

 heat, chemical decomposition, and other facts perceptible to 

 blind creatures, he with vast genius might have discovered that 

 a body existed at a great distance from the earth, from which 

 a peculiar influence was periodically rained upon the earth ; 

 that this influence could also be produced by fire and in other 

 ways by men living on the earth, and was in a given medium 

 inversely proportional to the square of the distance from the 

 source of light, as we call it. He might have discovered the 

 transparency and opacity of bodies, and the simpler laws of 



