SI 



THOUGHTS ON THE INFLUENCE OF ETHER 



discover another prolongation of light extending to the eastern horizon, and caused by the 

 part of the ring lying in the quadrant of the earth's orbit, through which it was about to 

 pass. The bright spot would finally reach a point 23° 28' south of the zenith, when the 

 sun would rise. 



These arc appearances which must of necessity ensue in the existence of the conditions 

 above proposed. They never having been observed, proves that the conditions do not 

 exist. There is no ring equidistant with the earth from the sun, and through which our 

 planet moves. 



Let us next suppose that the nebulous ring is within the earth's orbit, and to carry out 

 the scheme of those who favor the hypothesis, let the plane of the ring coincide with the 

 sun's equator. A ring so placed could never appear to extend ninety degrees from the 

 sun, which distance the zodiacal light often exceeds. Further, in the months of March and 

 September, when the earth is at its maximum distance from the plane of the sun's equa- 

 tor, a dark triangular space should be seen between the ring and the sun, especially if, as 

 Von Humboldt surmises, the ring is much compressed. 



So far from such an appearance being observed, the portion of the zodiacal light near 

 the sun is the brightest. These two objections arc sufficient to dispose of this conjecture. 

 The last branch of the ring hypothesis is, that the ring is beyond the earth's orbit. In 

 this case the brightness should extend from the point of the horizon where the sun had 

 disappeared, through all the visible signs of the zodiac to the eastern horizon. The part 

 having the greatest brightness should be nearest the zenith at midnight, because the par- 

 ticles of the ring in that position would be in the category of full moons, presenting the 

 whole of their illuminated surfaces to the earth. 



Has such an appearance ever been seen! If not, the conditions which should occasion 

 it do not exist. 



With regard to Cassini's idea of the sun's power to dart matter into space in the plane 

 of its equator, do not let it be confounded with the theory I am endeavoring to establish, 

 of the ascent of a current of ether in the equatorial region, from the cause of its lessened 

 specific gravity. 



The sun's power to dart matter into space, is purely conjectural. 



With the limited amount of our knowledge of nebulee, it would be an ungrateful task 

 to argue either for or against the competency of Professor Olmstead's hypothesis, to ex- 

 plain the cause of the zodiacal light. Were this point conceded, there arc other objec- 

 tions to it which should render its adoption by reasoning people an impossibility. 



The existence of the nebulous body, of which he furnishes us not only with the periodic 

 time, but also with the perihelion and aphelion distances, is an idea for the truth of which 

 there is not a shadow of evidence. 



